GB2063847A

GB2063847A - Phosphate grouting systems

Info

Publication number: GB2063847A
Application number: GB8035873A
Authority: GB
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1977-09-06
Filing date: 1978-09-06
Publication date: 1981-06-10
Also published as: DK392178A; BE870205A; GB2065256B; LU80204A1; PL209420A1; GB2003851A; CA1142556A; DE2835287C2; GB2003851B; FR2440487B1; AU3950778A; ZA785020B; IT1099025B; IN157596B; GB2063847B; FR2455691B1; NL7809056A; FR2455691A1; GB2065256A; AU524788B2

Abstract

An inorganic grouting system for use in a hole in combination with a reinforcing member comprises (a) an acidic reactive component comprising at least one acidic oxy phosphorus compound selected from phosphoric acids, anhydrides of phosphoric acids and salts of phosphoric acids with multivalent metal cations; (b) a basic reactive component comprising at least one particulate basic metal compound of a Group II or Group III metal capable of reacting with the oxy phosphorus compound(s) in the presence of water to form a monolithic solid; and (c) an aqueous component; the components being present in or outside a hole in a separated condition such that any substantial hardening reaction between the acidic and basic components is prevented, and when present outside the hole being adapted to be delivered into the hole separately or in a freshly combined condition; the basic metal compound(s) having a particle surface area of up to about 40 square meters per gram and constituting about from 5 to 35 percent of the total weight of the grouting composition, with the proviso that when the particles of the basic metal compound(s) have a surface area of less than 1 square meter per gram, more than about 95 percent of the particles pass through a 200 mesh screen; the ratio of the moles of the basic metal compound(s) to the moles of phosphorus pentoxide on which the oxy phosphorus compound(s) are based being in the range of about from 2/1 to 17/1; the amount of water present in the composition constituting about from 3 to 20 percent of the total weight of the grouting composition; a particulate aggregate being present in the composition in an amount such as to constitute about from 30 to 70 percent of the total weight of the composition.

Description

1 GB 2 063 847 A 1

SPECIFICATION

Phosphate grouting compositions The present invention relates to inorganic grouting systems and a compartmented package for use therewith 5 in a method of anchoring a reinforcing member in a hole, e.g., in a mine roof, wherein reactive inorganic components are introduced into a hole and allowed to react and harden therein around a reinforcing member so as to fix it firmly in the hole.

Anchor bolts are employed in various fields of engineering, for example as strengthening or reinforcing members in rock formations and in structural bodies. The bolts are inserted into drill holes in the formation 10 or body, and often are fixed or anchored therein, at their inner end or over substantially their entire length, by means of a reactive grouting composition which hardens around the bolt. When used in a mine roof, bolts grouted in this manner help significantly to prevent mine roof failure. Because unsupported rock strata have a tendency to move vertically and laterally, and this motion is what commonly causes the roof to fail, it is important that bolts be installed as soon as possible in a newly exposed roof and that the required strength 15 provided by the hardening of the grouting composition be developed rapidly, e.g., in a matter of a few minutes, or within an hour or so, depending on the type of mine. Rapid hardening also contributes to the efficiency of the bolt installation operation.

As a practical matter, the hardening or setting time of a bolt grouting composition must be sufficient to allow the reactive components thereof to be mixed and positioned around the bolt in the hole, e.g., at least 20 about 15 seconds, depending on anchoring length, both in the case in which the components are delivered separately into the hole and combined therein and mixed, e.g., by the rotation of the bolt, as well as when the components are delivered into the hole in combined and mixed form either before or after bolt insertion.

Beyond this necessary working time, the rate at which the composition approaches its ultimate strength should be as high as possible, e.g., for coal mine roof support the grout should attain about 80% of its pull 25 strength in an hour or less, and the ultimate pull strength should be at least about 175 kilograms per centimeter of anchoring length. Thus, the over-riding need in grouting systems for rock bolt anchoring is sufficient working time combined with high ultimate pull strength attained as rapidly as is required for a given use.

Reactive compositions which have been used in rock bolt anchoring include inorganic cement mortars and 30 hardenable synthetic resins, and these have been introduced into the drill holes through a feed pipe, or in cartridged form. In the latter case, the reactive components, e.g. a polymerizable resin formulation and a catalyst which catalyzes the curing of the resin, are introduced into the hold in separate cartridges or in separate compartments of the same cartridge. A rigid bolt penetrates, and thereby ruptures, the cartridge(s) and the package contents are mixed by rotation of the bolt. The grouting mixture hardens around the bolt so 35 as to anchor it in place.

In the case of inorganic cements, the pumping of a prepared cement mortar into a hole after a bolt is in position therein has been described, as has the driving of a bolt into cement mortar in a hole. In the former case, complete and uniform filling of the space around the bolt is difficult to ensure; and, in the latter case, the bolt has to be installed immediately after the mortar has been introduced, so that it is not feasible to fill a 40 large number of holes with the mortar first and subsequently to introduce the bolts, a more efficient procedure.

The present invention provides improved grouting systems for use in anchoring a reinforcing member in a hole by the reaction of the mixed components of a hardenable inorganic grouting composition so as to form a hardened grout around the reinforcing member, the improved systems having, in one case, a cement component in slush form to impart lubricity to the grouting composition for each insertion and rotation of a reinforcing member, and, in another case, a high-early-strength phosphate grouting composition, particularly suitable for use in coal mine roofs, that achieves a pull strength level of at least about 175 kg/cm anchoring length within an hour, and usually within 5-10 minutes.

In a preferred grouting system and anchoring method of the invention, which finds particular use in the reinforcement of mine roofs wherein the grouting composition has to set up fast enough to provide high strength in a very short time, grouting compositions are employed which harden relatively rapidly e.g., compositions containing calcined gypsum or Very High Early Strength cement (described in U.S. Patent 3,860,433) in the first component and water in the second component, or wherein the cement in the first component is an alkaline earth metal oxide or hydroxide and the second component contains a phosphoric 55 acid or phosphate solution.

The term '1norganic cement" as used herein to describe the particulate solid reactant in the first component or package compartment denotes a particulate inorganic composition that sets up and hardens to a strong, dense monolithic solid upon being mixed with a liquid and allowed to stand. The term includes hydraulic cements, i.e., those that are capable of setting and hardening without contact with the atmosphere 60 due to the interaction of the constituents of the cement rather than by the evaporation of a liquid vehicle or by reaction with atmospheric carbon dioxide or oxygen. Examples of such cements are Portland cements, high-alumina cements, pozzolanas, and gypsum plasters, which set up when mixed with water; lead oxide, which sets up when mixed with glycerin; as well as the more rapid-setting metal oxide or hydroxide compositions, e.g., magnesium oxide, which setup rapidly when mixed with phosphoric acid or phosphate 65 2 GB 2 063 847 A 2 solutions.

The term "slush" as used herein to describe the first component of the grouting composition denotes a solid-liquid combination of mud-like or sludgy consistency. The term includes solid-liquid combinations of varying degrees of mobility, but in all cases denotes combinations that are readily pumpable.

The term "liquid" as used herein to describe the second component of the grouting composition which is reactive with the inorganic cement in the first component is used in the conventional sense to denote single-phase materials as well as solutions. Also, the reactivity of this liquid with respect to the cement may be produced in situ when the components are brought together, as will be described hereinafter.

The nonreactivity of the liquid in the slush which constitutes the first component or which is present in the first package compartment refers to the substantial inertness of this liquid with respect to the solid cement and other materials present therein. Such liquid may, however, be reactive with a material in the second component or compartment, and may have some influence on the setting time and ultimate strength of the grout.

In another embodiment, the present invention provides a high-earlystrength phosphate grouting system for use in a hole in combination with a reinforcing member wherein a hardened grout is formed around the reinforcing member in the hole by the reaction of the mixed components of a hardenable inorganic grouting composition, said grouting composition comprising (a) an acidic reactive component comprising at least one acidic oxy phosphorus compound selected from the group consisting of phosphoric acids, e.g., H3P04, anhydrides of phosphoric acids, e.g., P205, and salts of phosphoric acids with multivalent, preferably trivalent, metal cations, preferably M(H2P04)3; (b) a basic reactive component comprising at least one particulate basic compound of a Group flor Group Ill metal capable of reacting with the oxy phosphorus compound in the presence of water to form a monolithic solid, preferably an alkaline earth metal compound selected from the group consisting of magnesium oxide, magnesium hydroxide, magnesium silicate, magnesium aluminate, and calcium aluminate; and (c) an aqueous component; these components being present in or outside a hole in a separated condition such that any substantial hardening reaction between the basic and acidic components is prevented, and when present outside the hole being adapted to be delivered into the hole separately or in a freshly combined condition; the basic metal compound(s) having a particle surface area of about from 0.1 to 40, preferably less than about 30, square meters per gram and constituting about from 5 to 35 percent of the total weight of the grouting composition, with the proviso that when the surface area is less than 1 square meter per gram more than about 95 percent of the particles pass through a 200 mesh screen (U.S. Standard Sieve Series); the ratio of the moles of the basic metal compound(s) to the moles of phosphorus pentoxide on which the oxy phosphorus compound is based being in the range of about from 2/1 to 1711; the amount of water present in 35 the composition constituting about from 3 to 20 percent of the total weight of the grouting composition; a particulate aggregate being present in the composition in an arnount such as to constitute about from 30 to percent of the total weight of the composition; and the components, when mixed, reacting without the application of heat thereto to form a hardened grout having a pull strength of at least about 175 kilograms per centimeter of anchoring length within an hour.

In a preferred embodiment, the acidic reactive component and at least a portion of the aqueous component are combined together in the form of an aqueous solution or mixture of a phosphoric acid or a phosphoric acid salt, and this solution or mixture is kept separate from the basic reactive component until use.

In this high-early-strength system, use of the reactive components in the form of a slush also is desirable 45 to achieve lubricity in the system for the easy insertion and rotation of a reinforcing member, and to make the component pumpable through small-diameter passageways. Hydrocarbons, polyols, and water are suitable slush-forming liquids.

10.

Brief description of the drawing

In the accompanying drawing, which illustrates specific embodiments of the compartmented package and inorganic grouting systems of the invention, Figure 1 is a perspective view of a portion of a compartmented package of the invention, which package has been cross-sectioned in the transverse direction so as to reveal more fully the internal structure thereof; 55 and Figure 2 is a plot of shear strength vs. time of a cement-water system of the invention.

Detailed description

In a method and system of this invention, an inorganic cement, e.g., a cement that sets by hydration or a metal oxide, is maintained in the form of a slush or sludgy mass together with a liquid with which it does not 60 react, e.g., an inert nonaqueous liquid, preferably a hydrocarbon, in the case of a cement that sets by hydration; and the slush is brought together and mixed, preferably in a drill hole, with a reactive liquid, e.g., water in the case of a cement that sets by hydration, and allowed to react in the hole around a reinforcing member. Cement in slush form has several advantages over the dry cement used in previous rock bolt packages. First, the nonreactive liquid imparts lubricity to the cement so that, when the two components of 65 3 GB 2 063 847 A 3 the grouting composition are packaged in a compartmented cartridge, a bolt can be inserted into the cartridge easily and rapidly. Also, the nonreactive liquid, if substantially immiscible with the reactive liquid, helps to reduce the possibility of the premature setting of the cement as a result of contact with the reactive liquid or its vapors, e.g., ambient moisture, during storage or handling, thereby affording a longer shelf life to the cartridged system. In addition, use of the cement in slush form enables the cement component to be metered accurately and handled in compact pumps for ease of packaging in high-speed form-fill machinery as well as for on-site feed operations. The cement component in slush form also is advantageous in that it is adapted to be delivered intermittently in relatively small quantities as is required for bolt anchoring in holes.

The combining of the inorganic cement with a nonreactive liquid in accordance with one embodiment of the present invention, while effectively isolating and fluidizing the cement prior to use, surprisingly does not 10 interfere with the interaction of the cement and reactive liquid after the grouting components have been mixed, relatively short setting times, rapid strength development, and high ultimate strengths being attainable despite the initial presence of the nonreactive liquid around the particles of cement in the slush.

The fact that the present slush system provides the rapid setting and strength development that is so important for mine roof support is indeed unexpected when consideration is given to the slush form of the 15 cement used, and the behavior of cement-oil combinations in such processes as the cementing of wells, well casings, or earth formations. For example, in the process for sealing off water-bearing formations adjacent to oil- or gas-bearing formations, known as "squeeze cernenting% and described, for example, in U.S. Patent 2,800,963, a cement slurry is pumped into a well until it is adjacent the water-bearing formation, and is held there in a static condition for about five minutes ("hesitation step") to allow water from the water-bearing 20 formation to come into contact with the slurry. Then high pressure is exerted on the slurry to squeeze it into the hydroca rbo n-bea ring and water-bearing formations. The slurry in the water-bearing formation hardens to selectively seal off that formation. In the "squeeze cementing" process and the well-cementing process of U.S. Patent 2,878,875 oil or a water-in-oil emulsion has been used in place of water in the cement slurry in order to delay the setting time of the cement. The development of strength in the cement in the described 25 well-sealing process has been reported to require several days'time, an indication that cement-oil slurries should be avoided in processes requiring a rapid setting of the cement.

In the high-early-strength phosphate grouting system of the invention, particulate materials in the grouting composition, e.g., the basic metal compound, aggregate, orthe oxy phosphorus compound, may be present in the dry state, but preferably they are present in the form of a solution, slurry, or slush with a 30 liquid with which they are nonreactive to any substantial degree. If water is kept separate from the oxy phosphorus compound, the latter and any aggregate which may be combined therewith form a slurry or slush with a nonaqueous liquid, preferably a hydrocarbon. Preferably, however, in the acidic component, phosphoric acid or a metal phosphate is present in aqueous solution or as a slurry or slush with water, which slurry or slush may also contain aggregate. The basic metal compound and any aggregate present therewith 35 preferably form a slurry or slush with a nonaqueous liquid such as a hydrocarbon or polyol, or with water or a water-containing liquid, water being used if the oxy phosphorus compound is separate from the basic metal compound and if the basic metal compound is sufficiently nonreactive with water that the basic component is not rendered resistant to bolt penetration by the occurrence of a hardening reaction therein.

Magnesium oxide, for example, can be used in a slush with water or a water-containing mixture such as an 40 aqueous glycol. A reaction may begin to take place between the oxide and water after some time depending on such factors as the calcination or fusion temperature of the oxide, the oxide/water ratio, oxide particle size, storage temperature, etc. This produces magnesium hydroxide, also a basic metal compound as defined herein for use in the basic reactive component. Thus, in a packaged system some change in the consistency of the basic component may be noted after a certain period of time, e.g., after about several 45 hours to several days, when magnesium oxide and water are present therein, but this does not involve hardening to the degree that bolt penetration becomes difficult. Also in a system wherein a freshly made magnesium oxide/water component is pumped into a hole, bolt insertion and reaction with the acidic component would occur before hydration of the oxide. Thus, in the sense defined above, water is a substantially nonreactive slush-forming liquid for magnesium oxide.

A wide variety of liquids can be used as slush-forming liquids in the grouting compositions. The specific choice in any given case will be made on the basis of the nature of the particulate ingredient, usually the cement or basic metal compound, any effect the particular liquid may have on the setting and strength-development time, and the cost of the liquid. Liquid hydrocarbons and mixtures containing such hydrocarbons are particularly advantageous from the point of view of setting time as well as cost, and therefore are preferred. A substantially nonvolatile liquid is preferred to assure stability under varying conditions of storage and use. Forthis reason, liquids boiling above about WC at atmospheric pressure are preferred. Thus, preferred hydrocarbon slush-forming liquids are 5-25 carbon atom aliphatic hydrocarbons such as hexanes, heptanes, and octanes; and aromatic hydrocarbons such as benzene and alkyl benzenes, e.g., toluene and xylene. Aromatic or aliphatic hydrocarbon mixtures such as gasoline, naphtha, kerosene, 60 paraffin oil, diesel fuel, fuel oils, lubricating oils, vegetable oils, e. g., linseed, tung, cottonseed, corn, and peanut oils, and crudes such as petroleum and shale oil also can be employed. For use in coal mines, the liquid in the slush must have a flash point above WC and should be low in volatile aromatics.

Although low-viscosity slush-forming liquids are preferred, thick liquids such as medium- or high-viscosity process oils, asphalt, grease, e.g., hydrocarbon oils thickened with soaps or other viscosity modifiers; animal 65 4 GB 2 063 847 A 4 fats, e.g., lard; and hydrogenated vegetable oils also can be used alone or combined with lower-viscosity liquids.

The slush-forming liquid also can be an alcohol, e.g., methanol, isopropanol, butanol, secbutyl alcohol, arnyl alcohol, a polyol such as glycol, or glycerol; a ketone, e.g., acetone or methyl ethyl ketone; cellosolve; an ester, e.g., dibutyl phthalate or acetyl tributyl citrate; dimethyl sulfoxide; or dimethylformamide; but the setting time of grouts made from slushes with these compounds may be much longer than that from slushes with hydrocarbons.

A particulate aggregate, preferably sand, may be present in a controlled amount as a filler in one or both of the components of the grouting composition, e.g., cement/water or basiclacidic components. In general, aggregate greatly enhances the strength of the hardened grout and also reduces the amount of cement or basic metal compound required. Other aggregate materials which can be used include particles of competent rocks or rockforming minerals such as granite, basalt, dolomite, andesite, feldspars, amphiboles, pyroxenes, olivine, gabbro, rhyolite, syenite, diorite, dolerite, peridotite, trachyte, obsidian, quartz, etc., as well as materials such as slag, cinders, fly ash, glass cullet, and fibrous materials such as chopped metal (preferably steel) wire, glass fibers, asbestos, cotton, and polyester and aramide fibers. Sands having different particle shapes and sizes can be used. Because of the need to be packed in a narrow annulus, the particles should have a minimum dimension no larger than about 3 mm. Mixtures of different aggregates also can be used.

For a given system, the shear strength of the hardened grout increases with increasing aggregate content up to about 60-70 percent by weight based on the total weight of the grouting composition. At the same time, 20 however, mixing of the components becomes increasingly difficult as the aggregate content increases. Also, too high an aggregate content, e.g., 90 percent or more based on the total weight of the grout results in a friable, impact-sensitive product which is of no use for anchoring a reinforcing member in a hole.

Therefore, while an aggregate content of up to about 80 percent can be employed, a content above about 70 percent is not preferred on the basis of ease of mixing and because there is little if any shear strength increase to be gained by exceeding 70 percent. Also, an aggregatelcement weight ratio in the range of about from 111 to 4/1 is preferred. Usually at least about 20 percent, and preferably at least about 40 percent, of the total weight of the grouting composition will be aggregate.

The manner in which the aggregate is distributed between the reaction components has no significant effect on the shear strength of the hardened grout. Thus, 100 percent of the aggregate can be in the cement 30 slush or basic component, or 100 percent in the component separated therefrom. Alternatively, aggregate can be distributed in any other proportions, e.g., 1/1, between two separated components. The specific aggregate distribution in any given case usually will be selected on the basis of that which gives a desired viscosity balance and ease of mixing. In a system in which the components are pumped and mixed at the site of use, it may be more convenient to include the aggregate in only one of the components.

In the inorganic grouting systems of this invention a preferred aggregate in the grouting composition is non-uniform or graded sand, i.e., sand having, in a size cut which includes 90 percent or more of the particles, maximum and minimum sizes that deviate by more than about 20 percent from the median particle size of the cut. It has been found that graded sand produces bolt-anchoring grouts having higher shear strengths than those made from compositions containing uniform sand. Inasmuch as graded sands having a 40 30 percent or more particle size deviation are commonly available, these often will find use in the present system. Although it is not intended that the invention be limited by theoretical considerations, it is believed that the advantageous effect of graded sand in the composition, as contrasted to uniform sand, may be related to a better distribution and packing of sand particles.

In the present grouting systems, the sand preferably is substantially free, and in any case contains no more 45 than about 10, and preferably no more than about 5, percent by volume, of particles larger than about 600 microns. Compositions containing more particles of this size have to have a higher liquids/solids ratio to facilitate pumping, e.g., during packaging operations, and the liquid content necessary for pumpability may result in a weaker grout. With particles larger than about 600 microns, there is a greater likelihood that the sand particles will be able to pierce through film cartridges of the grout, especially at the ends of the cartridge where the film is gathered together and held in place by a metal clip, thus resulting in leakage.

Larger than 600-micron particles also are deleterious to the composition in that they make the insertion of a bolt difficult. Such particles have a greater tendency to settle out of a slush, slurry or liquid, thereby causing cartridged grouts to be harder and stiffer in one area than in another, and making it difficult for a bolt to be inserted therein. Bolt insertion also is easier when the sand has round, rather than jagged, particles, and therefore round-particle sands are preferred.

When the components of the grouting composition used in the phosphate grouting system of the invention are combined and mixed, the reactive materials therein react rapidly around a reinforcing member to form a hardened grout of sufficient strength to firmly anchor the reinforcing member in a hole in rock strata so as to provide supportive strength to the strata. In quantitative terms, rapid reaction, in this case, 60 means that the phosphate grouting composition hardens in less than 30 minutes, usually in about 1-2 minutes, and reaches at least about 80% of its ultimate pull strength in less than 30-60 minutes, usually in less than 10 minutes. Firm anchorage means that the ultimate pull strength of the hardened grout is at least about 175 kilograms per centimeter of anchorage length.

The rapid attainment of high pull strength that characterizes the present phosphate grouting system 65 1 10 GB 2 063 847 A depends on a unique combination of features of the grouting composition, including the surface area and content of the particulate basic metal compound(s), with respect to the total grouting composition and also with respect to the oxy phosphorus compound(s) the water content, the aggregate content, and in a preferred case, the presence of an oxy phosphorus compound (trivalent metal salt of phosphoric acid) that forms a cross-linked polymeric network in the hardening reaction. The reactive entity in the acidic component is a phosphoric acid or an anhydride thereof, or an acid salt of a phosphoric acid with a multivalent, preferably trivalent, metal cation. This entity reacts with the reactive entity in the basic component which is a basic Group 11 or Ill metal compound that is capable of reacting with the phosphoric acid or an anhydride or salt thereof to form a monolithic solid. Such compounds include, for example, alkaline earth metal oxides and hydroxides, e.g., magnesium oxide, magnesium hydroxide, and calcium 10 oxide. aluminum oxide and hydroxide; ferric hydroxide; alkaline earth metal aluminates, e.g., magnesium aluminate and calcium aluminate; and magnesium silicate. Magnesium oxide and hydroxide are preferred on the basis of availability. Aluminum oxide, e.g., A1203.3H20, desirably is used in mixture with magnesium oxide or hydroxide, especially when the oxy phosphorus compound is phosphoric acid, H3P04. With such mixtures, up to about 13%, and preferably about from 5 to 7% of the grouting composition, is aluminum oxide.

When the acidic, basic, and aqueous components are combined and mixed, the phosphoric acid or phosphate reacts with the particulate basic metal compound in the presence of the water to form a hardened structure wherein the particles of aggregate and any unreacted portions of the particles of the basic metal compound are bound together. It has been found that monovalent salts of phosphoric acid, e.g., the ammonium phosphates which figure prominently in the prior art on patching systems, etc., do not develop the early pull strength required for bolt anchoring, and it is believed that this shortcoming is due, at least in part, to the inability of such salts to form a three-dimensional polymeric network crosslinked by a multivalent metal ion. e.g., Al'3. For this reason, salts of phosphoric acids with trivalent metal cations, e.g., AI 13. are preferred phosphoric acid salts in the acidic component. Phosphoric acid (and P205), and acid aluminum 25 salts thereof, especially the common aluminum dihydrogen phosphate and A]H3(P04)2.H3P04, are most preferred on the basis of availability.

In the present system, the grouting composition is in its pre-mixed form, and for this reason the acidic, basic, and aqueous components are present in a separated state. Separation of these components is such that one component is excluded from the presence of the othertwo, which in turn may be together or also 30 separate. In most cases, it will be more convenient, and therefore preferred, to have the phosphoric acid or phosphate present in its hydrous form, i.e., as an aqueous solution or slurry, and in such cases the combined acidic and aqueous components will be maintained separate from the basic component. which can also contain water and/or a nonaqueous liquid. Alternatively, a substantiallyanhydrous acidic component, e.g., one containing P205, can be combined with a substantially anhydrous basic component, and these combined components kept separate from the aqueous component; or the basic and aqueous components can be combined and kept separate from the substantially anhydrous acidic component. In both of the latter cases, the substantially anhydrous components can be slurries or siushes with nonaqueous liquids.

The particulate basic metal compound, e.g., magnesium oxide, has a surface area in the range of up to about 40 square meters per gram, and constitutes about from 5 to 35 percent of the total weight of the grouting composition. Grouts having less than about 5 percent of the basic metal compound do not develop a sufficiently high ultimate pull strength regardless of the setting time. A preferred minimum is about 8 percent. There appears to be no advantage in exceeding a basic metal compound content of about 35 percent. and on an economical basis more than about 25 percent generally will not be used. These percentages refer to the total of all such reactive basic metal compounds present.

The preferred basic metal compound has a surface area of less than about 30, and most preferably 1 to 20, square meters per gram. This means that the preferred magnesium oxide is the so-called "chemical grade" magnesium oxide, prepared by calcining magnesium carbonate at temperatures in the 900-1200'C range. Calcined-grade (surface area generally well below 1 square meter per gram) and fused (surface area below about 0.1 square meter per gram) magnesium oxide also can be used, however. Fora given concentration of 50 the basic metal compound, the selected surface area thereof should be sufficiently low to assure the necessary working time (e.g., about 15-45 seconds to allow insertion of a bolt into the grout and mixing), but sufficiently high to give a hardened grout of a desired strength in the desired time. Generally, this means that high concentrations are used with low surface areas and vice versa. With low-surface area compounds, e.g., below about 1 square meter per gram. more than about 95 percent of the particles should pass through a 55 200-mesh screen (U.S. Standard Sieve Series) to assure an acceptable reaction rate. High-surface-area MgO preferably is used with aluminum phosphate.

High early strength also requires that the basic metal compound concentration be sufficiently high with respect to the amount of phosphoric acid (or its anhydride) or metal phosphate present in the acidic component. The molar ratio, for example, of the basic metal compound in the oxide form to the oxy phosphorus compound in the form Of P205 should be at least about 2/1. preferably at least about 4/1. Generally, there is no advantage to exceeding this ratio to any large degree, e.g., above about 17/1, inasmuch as a cheaper filler can be used to increase the solids content without deleterious effect.

As was mentioned previously, a phosphoric acid or a metal phosphate preferably will be present in the hydrous form, i.e., as an aqueous solution or slurry, and in this embodiment the aqueous component will, at 65 6 GB 2 063 847 A 6 least in part, be found combined with the acidic component. In this case, the basic component must be maintained separate from the acidic component, and may or may not contain water.

Water is needed in the grouting composition so that the acidic oxy phosphorus compound will be in the form of a well-dispersed system which allows for mobility of ions. At least about 3 percent of the total weight of the grouting composition will be water, larger concentrations being used with compositions containing larger amounts of oxy phosphorus compound. However, the water content of the composition has to be controlled so as not to exceed about 20 percent by weight, or the rate of strength development will be deleteriously affected. Accordingly, the concentration of aqueous phosphoric acid or aqueous metal phosphate in the acidic component is at least about 60 percent by weight. This concentration can be much higher, e.g., when water is also present in the basic component. Supersaturated aluminum phosphate solutions and the solid-liquid mixtures which result when crystallization takes place from these metastable solutions are preferred over less concentrated solutions because they produce stronger grouts.

The hardened grout produced around the reinforcing member in the method of this invention forms as a result of the reaction between inorganic reactants. Organic resin-curing systems are not required, and the reactants which undergo a hardening reaction therefore are substantially all-inorganic. The development of strength in the hardened grout sufficient to anchor a bolt securely in place in a hole in a mine roof, and provision of the components in a form such that they can be delivered and mixed conveniently, require a balance of the content of inorganic cement, slush-forming liquid, reactive liquid, and aggregate, if present.

Onthis basis, although it is possible to make a marginally satisfactory grout from compositions containing 5-10 percent of a cement that sets by hydration, in order to provide maximum strength capability it is 20 preferred that the amount of such cement constitute more than 10 percent of the total weight of the composition. Sufficient reactive liquid should be present to react with such cement, e.g. sufficient to give a water/cement weight ratio of at least about 0.1, and preferably at least about 0.3. In order to be able to allow forthe incorporation of a sufficient amount of aggregate and reactive liquid into this system, the amount of cement will not exceed about 80 percent of the total weight of the two components; and a maximum cement 25 content of about 50 percent is preferred inasmuch as no advantage in terms of final strength is seen in exceeding this amount.

The specific amounts of liquids used in the composition will depend on the amount of solids present, ease of delivery, mixing, etc. From strength considerations, it is undesirable to exceed significantly the stoichiometric amount of reaction liquid and the amount of slush-forming liquid required to give the 30 necessary lubricity and deliverability (e.g., pumpability). A liquids/solids weight ratio of the combined components in the range of about from 0.1 to 0.6 is satisfactory from the viewpoint of strength, and handling and mixing considerations. In accordance with these considerations, the water/cement weight ratio in cement systems that set by hydration generally will not exceed about 1.0, preferably 03; and the amount of water, based on the total weight of the two components, will be about from 2 to 50, and preferably 5 to 30, 35 percent. Also, the amount of slush forming liquid will vary about from 5 to 50, preferably 8 to 20, percent of the total weight of the composition; or about from 10 to 75 percent, preferably 35 to 65 percent, of the weight of the cement.

The reactive liquid in the second component of the grouting composition, and the acidic component of a basiclacidic phosphate system containing aqueous phosphoric acid, preferably are in thickened form, e.g., 40 contain a thickening agent. This reduces the chance that the liquid will run out of an upward-slanting hole or soak into fissures or pores in the hole wall. The thickening agent is a solid material that absorbs water, is hydratable, or is somewhat water-soluble, and can be an inorganic material such as clay or fumed silica, or an organic material. Organic thickening agents that can be used include ca rboxymethylcel 1 u loses, polyvinyl alcohols, starches, carboxyl vinyl polymers, and other mucilages and resins such as galactomannans (e.g., 45 guar gum), po Iyacryla m ides, and poiVethylene oxides. Polyethylene oxide, polyacrylamide, and mixtures of the two are preferred. These two materials not only provide the thickening effect needed to reduce the chance that the water will run out of an upward-slanting hole or soak into fissures or pores in the hole wall, but are lubricants as well, in the sense that they facilitate the insertion of a bolt into an aggregate-water slush, the aggregate having less tendency to settle or pack in water containing these materials. Moreover, 50 the beneficial effect of these thickenerllubricants, is achieved with sufficiently small amounts thereof that grout shear strength is not severely compromised. In phosphoric acid systems because of their stability therein polyethylene oxides are preferred organic thickeners.

The amount of thickening agent in the reactive liquid component, e.g., the acidic reactive component, depends on the specific material used, and specifically on the degree of thickening of the liquid component 55 attainable therewith, a function generally of the molecular weight and degree of substitution of the material, and depends also on other solid materials which may be incorporated in the reactive liquid component.

Generally, the amount of thickening agent will be in the range of about from 0.1 to 1, preferably to 0.5, percent of the total weight of the composition, the lower end of the range being used with materials of higher molecular weight andlor having more hydrophilic groups. In the case of the organic polymers, more than about 0.2 percent, based on the total weight of the composition, usually will not be necessary.

One or more surface-active agents can be incorporated into the reaction system, in either one or both of the components. A surface-active agent in the cement slush or in the reactive liquid component containing suspended sand particles produces the consistency of a smooth paste, which results in improved ease of mixing of the components. The surface-active agent should be soluble in the liquid of the component in 65 c 7 GB 2 063 847 A 7 which it is used, and should give a hydrophilic-lipophilic balance value of about from 8 to 14, as determined according to the methods outlined in "The Atlas HLB Systern", Atlas Chemical Industries, Inc., 1962. About from 0.1 to 10, and preferably from 1 to 5, percent of surface-active agent is used. However, since the presence of a surface-active agent can result in a hardened grout of lower shear strength, it is necessary to assess what effect, if any, the surfactant under consideration has on strength, and to balance this finding against the advantage to be gained in ease of mixing. Surfactants which can be used include oleic acid, sorbitan monoffleate and monolaurate, polyoxyethylene monoffleate and hexaoleate, polyoxyethylene sorbitan trioleate and monoiaurate, and poiyoxyethylene tridecyl ether. Of these, oleic acid is preferred both on the basis of degree of effectiveness and cost.

The present grouting system can be used wherever structure reinforcement is required, e.g., in rock 10 bolting or roof bolting in coal or metal mines, or to secure bolts in holes drilled in concrete structures. If the components of the system are delivered into the drill hole by pumping, they preferably are pumped into the hole separately and combined and mixed therein before or after bolt insertion. Alternatively, pumped components can be combined just outside the hole and mixed there or in the hole. Preferably the components of the grouting composition are delivered into the drill hole, and the reinforcing member is introduced into the composition before any substantial hardening of the composition has occurred, whereby grouting composition is forced into an annulus formed between the reinforcing member and the wall of the hole. The components are thereafter mixed, preferably by the rotation of the reinforcing member, to form the hardened grout. A preferred system comprises a frangible compartmented package having at least two components in separate compartments, the package being broken by penetration by the reinforcing member. One such package is shown in Figure 1. In Figure 1, a tubular member 1 of substantially circular transverse cross-section and a diaphragm 2 are constructed by wrapping a single web of pliable film material in a manner such as to form a convoluted tube having a partially single-ply and partially double-ply wall, the inner ply of the double-ply wall portion forming diaphragm 2. The two plies of the double-ply portion are sealed together near inner edge 3 and outer edge 4 of the web so as to form linear junctures or 25 seals 5 and 6, respectively. Tubular member 1, diaphragm 2, and junctures 5 and 6 define two separate compartments 7 and 8. At each end of the compartmented tubular member, one of which is shown in Figure 1, the end portions of tubular member 1 and of diaphragm 2 are collectively gathered together and closed by closure means 9. Compartment 8 is filled with Component A described in Example 1 which follows, and compartment 7with Component B described in the same example.

In use, this package is inserted into a drill hole, and a bolt is forced into the package, tearing the film and penetrating a part, or the full length, of the package. The components are mixed by rotation of the bolt, and subsequently react with hardening so as to secure the bolt in the hole.

The invention will now be illustrated by way of the following examples. Parts and percentages are by weight. In the Examples, the following words are registered trademarks viz. "Cellosolve% "Instron", 35 ---Nujo1%---Sakrete%"PolVox%---Methoce1% "Jaguar", "Span", "Tween" and "MarcoV.

Example 1

A two-component reaction system of the following composition was made:

ComponentA Component 8 19.05% cement 0.12% polyacrylamide 28.57% sand 28.57% sand 11.43% oil 12.26% water 45 The percentages are percent of the ingredients by weight, based on the total combined weight of the two components. The cement was 'Wery High Early Strength- (VHE) cement, manufactured by U.S. Gypsum Co., a fast-setting cement that sets by hydration, described in U.S. Patent 3, 860,433. This cement contains (by weight) about 20-40% 3CaWA1203-CaSO4 and about 10-35% chemically unbound CaS04, the remainder being substantially P-2CaO-SiO2. The sand was Ottawa Silica Company's Banding Sand. This sand has round particles, 94% of which are in the size range of 74 to 210 microns. The median particle size is 142 microns, and the deviation 48%. The sand has 99% of its particles smaller than 420 microns. The surface area of the sand is about 160 cm2/9. The polyacrylamide was "Polyha1V 295, made by the Stein Hall Company. The oil was kerosene. The slush of cement, sand, and oil was kept separated from the thickened water/sand 55 combination. For strength testing, the two components were mixed to substantially homogeneity, whereupon oil was exuded therefrom, and the resulting paste-like composition hardened.

The shear strength of the grout, measured after 24 hours, was 336 kg/sq. cm. The method of measurement was the following:

A sample of the freshly mixed grout was placed on polyethylene terephthalate film, and a stainless steel 60 ring, 15.9 mm in diameter and 2.92 mm high, was placed on the grout. A piece of polyethylene terephthalate film was placed over the ring, and the latter then was pressed evenly into the grout by means of a block of wood. The resulting "shear button" of the grout was placed on an Instron testing machine (conforming to ASTM Method E4, Verification of Testing Machines), and tested (24 hours after mixing) for shear strength by the method of ASTM D732 (ASTM is the American Society for Testing and Materials). In this test, a plunger 65 8 GB 2 063 847 A 8 was brought down onto the grout at a rate of 12.7 mm per minute. The shear strength was calculated from the applied force to cause failure, according to the following equation:

shear strength = Force Specimen thickness x n x diam. of 5 punch The grout also was evaluated after 24 hours in terms of its average pull strength, i.e., 450 kg/cm, according to the following procedure:

Freshly mixed grout was placed in a section of 2.54-cm threaded pipe. and a standard 1.59-cm-diameter steel blunt reinforcing rod was inserted into the grout. The excess grout which was squeezed out during insertion of the rod was scraped off, and the pipe-rod assembly was placed into a testfixture mounted in an Instron Universal Testing Machine. The rod was then pulled (24 hours afterthe mixing of the grout) by applying a measured upward force to the bolt while the pipe section of the pipe-rod assembly was held stationary in the fixture. The force at which the first discontinuity in the recorded force vs. deflection curve was observed was the pull strength.

Example 2

Four dual-compartment frangible packages in the form of 46-cm-long, 2.3cm-diameter---chub- cartridges as described in U.S. Patents 3,795,081 and 3,861,522 and as is shown in Figure 1 herein, and containing a 20 two-component reaction system of the invention, were made from a web of polyethylene terephthalate film.

One compartment contained a slush of the cement, sand, and oil described in Example 1. The other compartment contained water and the sand and thickener described in Example 1. The ingredients content based on the total combined weight of the contents of the two compartments was as follows:

Cartridges aandb Cartridges candd cement 34% 32% oil 13% 13% 30 sand 31.4% 30.2% water 21.6% 24.8% thickener 0.10% 0.10% 26% in the cement slush; 5.4% in the water 24% in the cement slush; 6.2% in the water Each sealed cartridge was placed in a 2.54-cm-diameter steel pipe having a rough wall and a welded closure at one end (simulated drill hole). The pipe was held in an upright position in a vise with the closed end uppermost. A headed reinforcing rod (bolt) 15.9 mm in diameter was inserted into the cartridge with a rotating upward motion, and spun at 300 rpm to mix the contents of the package. A washer closed off the 40 bottom end of the pipe. Ambient temperature was 27'C. After one hour the pull strength of the grout was determined by applying force to the headed end of the bolt in a downward direction at a rate of 1.27 cm per minute. The results are shown in the following table:

Mixing Force 45 Time Required To Cartridge (sec) Cause Slippage a 7.5 10.2 x 103 kg b 20 12 X 103 kg 50 c 7.5 9.1 X 103 kg d 17.5 9.2 X 103 kg Example 3

A cement-oil slush and an aqueous sand mixture in the proportions 28.57% cement, 14.29% oil, 42.86% sand, and 14.29% water (same cement, oil, and sand as described in Example 1) were mixed thoroughly, and shear buttons prepared from the freshly mixed grout as described in Example 1. The buttons were tested for shear strength after seven different periods of time, according to the procedure described in Example 1. The results are shown in Figure 2, where shear strength is plotted vs. time on a logarithmic scale. It is seen that this grout achieved a shear strength of 70-140 kg/sq cm (equivalent to the strength of coalmine roof strata) in 60 to 90 minutes, and well over 90 percent of its full strength (equivalent to the strength of metal mine roofs) in less than 4 hours.

t 9 GB 2 063 847 A 9 Example 4 (1) The following separate components were prepared:

ComponentA (parts) cement (26.32) sand (19.74) oil (14.47) Component 8 (parts) sand (19.74) 1 % aqueous solution of polyacrylamide (19.74) The sand and oil were the same as those used in Example 1. Five different mixes of Component A were 10 prepared, each with a different cement. The 24-hour shear strength of the grout prepared by mixing each one of the five A Components with Component B was measured as described in Example 1. The results were as follows:

Cement in ComponentA Shear Strength (kglsq cm) 15 WE 147 Ordinary Portland (Type il) -5 ---RapidRock"(a) -4 20 Huron Regulated Set Portland Cement (RSpC)(b) 0 Hydrostone Super X(') 42 25 (a) Reported as producing a fast-setting (15 min) pourable grout when mixed with water, setting to 350 kg/sq cm in one hr (Tamms industries Co. Ti-103,1974) (b) Type Ill, contains calcium aluminum fluorite, reported to be fast- setting and able to gain strength at a 30 rapid rate during the early ages of the concrete (National Gypsum Co., Huron Cement Div. data sheets) (c) Calcined gypsum, U.S. Gypsum Co.

(2) Strength/setting time characteristics of cements used in Part (1) in the absence of oil.

Each of the cements (20 parts) listed in Part (1) above was mixed with 30 parts of the sand, and an amount of water was added according to the manufacturer's specifications to achieve maximum strength at 35 minimum age. The number of minutes required for each oil-free grout to become hard is given in the following table:

Cement Hardening Time 40 WE <20 min Ordinary Portland -24 hrs "Rapid Rock" <10 min Huron RSPC <20 min Hydrostone Super X <20 min 45 The following table gives the compressive strengths (manufacturer's specifications) and 24-hour shear strengths (measured as described in Example 1) for oil-free grouts made from the cements listed in Part (1) above. The shear test specimens were prepared from grouts made by mixing 10 parts of the cement with 15 parts of sand and 3.54.5 parts of water (according to manufacturer's specifications).

Compressive Strength Shear kgIsq cm (time in Strength Cement hrs) kgIsq cm 55 VHE >350 (24) 375 Ordinary Portland < 140 (24) 84 "Rapid Rock" 350(1) 251 Huron RSPC >210 (24) 452 Hydrostone Super X >455 (1) (wet) 265 60 >945 (1) (dry) GB 2 063 847 A Example 5

The effect of sand content on the 24-hour shear strength of the grout was examined with a system wherein 28.6 parts of the cement described in Example 1 and 14.3 parts of the oil described in Example 1 formed one component, and 14.3 parts of a 1 percent aqueous polyacrylamide solution formed the other component, and an amount of sand was divided evenly between the two components. The results are shown in the following table:

Sand Parts % 0 214 14.9 242 26 294 46.8 737 Measured as described in Example 1.

Shear Strength (kglsqcm) Example 6

A reaction system in which 18.7 percent cement and 13.1 percent oil (same cement and oil as in Example 1) were in Component A, 12.1 percent of a 1 percent aqueous solution of polyacrylamide was in Component B, 20 and 56.1 percent sand (the sand used in Example 1) was located as indicated in the following table, was tested for shear strength as described previously:

24-hr Shear Strength kglsq cm 25 100% in Component A 327 100% in Component B 288 (50% in Component A) 292 (50% in Component B) 30 These results show that the distribution of sand between the components has no significant effect on the shear strength of the hardened grout inasmuch as all of the values are within 10 percent of the average value, a deviation possibly due to experimental error in the test procedure.

Example 7

Fibrous materials were added to the cement-oil slurry in the following experiments.

(a) A grout made by mixing a cement-oil slush containing 28.49 parts VHE cement, 14.25 parts of the oil described in Example 1, and 0.28 part of 1.27-2.54-cm-long glasswool fibers with an aqueous sand suspension containing 42.74 parts of the sand described in Example 1, 14. 25 parts of water, and 0.14 parts 40 of polyacrylamide, had a 1 -day shear strength (method of Example 1) of 291 kg/sq cm. The same slurry without the glasswool gave a grout having a 1 -day shear strength of 235 kg/sq cm.

(b) The 4-hour shear strength of a grout made by mixing 40.61 parts VHE cement and 18.27 oil (same as that of Example 1) with 20.30 parts sand (same as that of Example 1) and 20.30 parts of a 1 percent aqueous solution of polyacrylamide was increased from 98 kg/sq cm to 123 kg/sq cm by the addition of 0.51 percent of 45 1.27-cm-long KeviarO" (aramide) fibers to the cement slush.

1 11 GB 2 063 847 A 11 Example 8

Different organic liquids were tested as slush-forming liquids by combining 20 parts of VHE cement with 10 parts of the liquid being tested, adding 10 parts of water to the resulting slush, mixing the cement and water components, and testing the resulting grout qualitatively for hardness. The results were as follows:

Slush-Forming Agent is pentane hexane heptane benzene toluene xylene gasoline fuel oil +2 kerosene Nujol methanol Grout Characteristics hardin -7 min hardin -7 min hardin -7 min hardin -5 min hardin -10 min hardin -7 min hardin -8 min hardin -9 min hardin -6 min hardin -23 min hard in -7 hr 5.

When the above-described procedure wasfollowed withoutthe addition of a slush-forming liquid, the 20 grout became hard in 5 minutes.

Example 9

One of the benefits achieved by employing the cement in the form of a slush was studied by comparing the force required to insert a bolt into the slush as contrasted to that needed to penetrate a dry cement. A 2.54 25 cm-in ner-dia meter steel pipe was filled with the cement component, and a 15.9-mm-diameter steel reinforcing rod was moved downward into the component in an Instron machine at a rate of 51 cm per minute. A force of only about 0.2 kg was required to penetrate 2.5 cm of a slush consisting of 44.44 percent cement, 33.33 percent sand, and 22.22 percent Napoleum 470 (a predominantly aliphatic kerosene) or Circosol 410 (a naphthenic based oil made by the Sun Oil Company).

In contrast, a force of 1600 kg (maximum available on the Instron machine) was required to insert the bolt about 2.54 cm deep into a mixture of 57.1 parts dry cement and 42.9 parts sand.

Example 10

The following separate components were prepared:

ComponentA (parts) Component 8 (parts) cement (28.57) oil (14.29) sand (42.86) water (14.29) The cement and oil were the same as those used in Example 1. Three different mixes of Component B were prepared, each with a different sand. The 24-hour shear strength of the grout prepared by mixing each one of the three B components with Component A was measured as described in Example 1. The results were as 45 follows:

SandIn ComponentB Banding Sand Sand Characteristics See Example 1

ShearStrength (kgIsq cm) 246 "Sakrete" Sand 95% 147-420 [t; median (-35 mesh) 288 It; deviation 45% 100% <540pt. Jagged. 235 55 Sawing Sand 95% 297-420 [t; median (Ottawa Silica 358 [t; deviation Co.) 17%.96% <540 pt.

Round 117 Ali-purpose "Sakrete" sand packaged by H.T. Campbell Company, Towson, Maryland 12 GB 2 063 847 A 12 Example 11

The procedure described in Example 10 was repeated with seven different graded sands in Component B. In this case, the cement content was 18.5 parts, oil 14.8 parts, sand 55.6 parts, and water l l. 1 parts. All of the sands had round particles and were products of the Ottawa Silica Company, Ottawa, Illinois, and described 5 in Ottawa's Product Data Sheet OD 3-74-0. The results were as follows:

Particle Size (g) Shearstrength Sand Range Median Deviation Max. KgIsq. em (a) Special Bond 96%105-297 201 48% 100% <540 223 (b) Bond Sand 97%105-297 201 48% 100% <540 255 (c) Fine Special 96%140-420 280 50% 100% <540 250 Blend (d) 50-Mesh 91%105-210 157 33% 99% <420 224 15 (e) Banding Sand 94% 74-210 142 48% 99% <420 224 (f) 90 Shell 96% 74-210 142 48% > 99% <420 231 (g) F-140 98% <53-147 -100 47% > 99% <297 171 Example 12

The procedure described in Example 10was repeatedtwice, oncewith a graded sand, Le.,the -35 mesh "Sakrete" described in Example 10, and oncewith a uniform sand, i.e., the 297-420 micron cut---from the -35 mesh "Sakrete". The median particle size of the uniform sand was 358 microns, and the deviation 17%. The 24-hour shear strength of the grout containing the graded sand was 472 kg/sq em, and that of the grout 25 containing the uniform sand 354 kg/sq em.

Example 13

Two different sands were tested with respect to their settling rates in thickened water, as an indication of their behavior in stored two-compartment cartridges having a cement slush in one compartment and a sand/water mixture in the other. Segregation of the sand results in an asymmetrical package, which is harder 30 and stiffer in one section than in another, making bolt insertion more difficult.

Both sands were "Sakrete". One was a coarse sand consisting solely of particles largerthan 500 microns (53% larger than 833 microns, 12% larger than 2.36 mm, the remainder between 540 and 833 microns). The other was a fine sand consisting of the -35 mesh---Sakrete-described in Example 10.Tubes 31 em long and having a 2.5-cm-diameter were filled with a 1 % aqueous solution of polyaerylamide, and the sand was added 35 to the tubes. The settling rate at 200C was about 20 minutes for about 90% of the coarse sand, and about 46 minutes for about 90% of the fine sand.

Example 14

The following separate components were prepared:

ComponentA (parts) Component 8 (parts) cement (27.8) sand (41.6) oil (13.9) 1 % aqueous thickener 45 solution (16.7) The cement, oil and sand were the same as those used in Example 1. Different mixes of Component B were prepared, each with a different thickener. The 24-hour shear strength of the grout prepared by mixing each of the A Components with Component B was measured as described in Example 1. The results were as follows: 50 13 GB 2 063 847 A 13 Thickener Shear Strength Chemical (kgIsq cm) Type Commercial Designation Polyacrylamide Polyacrylamide Polyacrylamide Polyethylene oxide Sodium ca rboxymethyl cell u lose Sodium carboxymethylcellulose Methylcellulose derivative Methylcellulose derivative Methylcellulose derivative Methylcellulose derivative Methylcellulose derivative Methylcellulose derivative Natural gum Natural gum Polyhall 295 (Stein Hall) Polyhall M40 (Stein Hall) Polyhall 650 (Stein Hall) Polyox 301 (Union Carbide Sodium CIVIC (Du Pont) Sodium CIVIC (Hercules) Methocel HD (Dow) Methocel AMS (Dow) Methocel J75MS (Dow) Methocel E4M (Dow) Methocel K4M (Dow) Methocel K15M (Dow) Jaguar 180 (Stein Hall) Jaguar 180 (Stein Hall) 139 164 113 81 148 182 16 50 27 38 20 17 163 67 When the above-described procedure was repeated with no thickener, the shear strength was 333 psi.

Example 15

A 2.54-cm inner diameter steel pipe was filled with a mixture of 75% sand (-35 mesh "Sakrete" made by 25 H.T. Campbell Company, Towson, Maryland) and 25% of a 1% aqueous solution of a thickener, and a 15.9-mm diameter steel reinforcing rod was moved downward into the mixture in an Instron machine at a rate of 51 cm per minute. The force required to insert the rod 2.54 cm was measured. The results were as follows:

Thickener Polyox 301 Methocel HD Polyhall 295 Jaguar180 Sodium CIVIC Hercules CIVIC Force Needed For2.54 cm Penetration (kg) 22 57 91 94 149 Aforce of 608 kg was required when no thickenerwas present, and 588 kg when no water orthickenerwas present.

Examples 14 and 15 showthat, of the thickeners which permit a shear strength of 70-140 kg/sq cm to be retained, polyethylene oxide and polyacrylamide are superior in ease of bolt penetration, and thus are 45 particularly suited for use in cement grouts for anchoring rock bolts.

Example 16

When the procedure described in Example 15 was repeated with the use of the sand described in Example 1 (Banding sand), a force of only 0.2 kg per 2.54 cm of insertion was required for the Polyhail 295 and the 50 Polyox 301 solutions.

Examples 17-21 A surfactant (0.2 part) was added to a grout of the following composition:

ComponentA Component 8 55 VHE cement (19.76 parts) sand (29.64 parts) sand (29.64 parts) 1% aqueous solution of oil (7.90 parts) polyacrylamide (12.85 parts) 60 Same as in Example 1 The grouts obtained upon mixing of Components A and B were tested after 24 hours for shear strength as described in Example 1. In all cases in which a surfactant was employed, the component containing the surfactant was a smooth paste, and mixing was easy.

Rb G) CD N 0 a) W OD t 24-hour Shear Component Strength Example No. Surfactant Chemical Compound HL8 Value ConIg. Surfactant kglsq cm 17 none 245 18 Tween 81 Polyoxyethylene monobleate 10 A 133 19 Tween 85 Polyoxyethyiene sorbitan trioleate 11 B 72 Span 20 Sorbitan monolaurate 8.6 A 39 21 G1086 PolVoxyethylene hexaoleate 10.2 A 55 Hydrophilic-Lipophilic Balance ComponentAwas 19.01 parts cement, 28.52 parts sand, and 11.31 parts oil Component B was 28.52 parts sand and 12. 36 parts polyacrylamide solution 11 l 4 is GB 2 063 847 A is Example 22

The following components were prepared 1 ComponentA VHE cement (31.16 parts) oil (6.23 parts) Span 80 (0.12 part)HI-B=9.1 Tween 85 (0. 16 part) Same as in Example 1 Sorbitan Monobleate ComponentB sand (46.74 parts) 1% aqueous solution polyaerylamide (15.58 parts) 6 Component A (113 parts) and Component B (187 parts) were packed into the separate compartments of the polyethylene terephthalate film cartridge described in Example 2. The cartridged grout was subjected to a 15 pull strength test in a simulated drill hole as described in Example 2. Twenty-four hours after the components had been mixed, the pull strength of the hardened grout was 11 X 103 kg.

Example 23

The following two components were made: 20 ComponentA Component 8 Hydrostone (2000 parts) Water (1758 parts) Marcol 90 N.F. (369 parts) Methocel 65 (35 parts) 25 Light Mineral HG (Dow) Oil (Exxon) Stearic acid (22 parts) Sodium stearate (114 parts) a commercial cement consisting essentially of calcined gypsum Component A was made by heating a mixture of the oil and stearic acid to 570C to dissolve the stearic acid, and mixing the resulting solution with the hydrostone in a turbine mixer. Component B was made by heating a mixture of the ingredients to 570C to dissolve the sodium stearate and produce a thick paste. When Components A and B were mixed in the weight ratio of 6.38/1 A/B, the mixture set up into a solid within a few 35 minutes.

One compartment of a 61-cm-long dual-compartment cartridge described in Example 2 was filled with Component A and the other compartment with Component B in the weight ratio of 6.38 parts of Component A for every part of Component B. The filled cartridge was stored for 10 days and then tested for rock bolt anchoring substantially as described in Example 2. A 76-cm-long rock bolt was inserted into the cartridge at a 40 rate of somewhat less than 1.2 meters per 15 seconds, while the bolt was spun at 450 rpm. The bolt was spun for 5 or 10 seconds after insertion.

When the grouted bolt was pull-tested after 12.5 minutes, no slippage occurred until a force of 8200 kg had been applied.

Example24

A grouting composition was prepared which had the following components:

Acidic andAqueous Basic Component Components 50 13.2% M90 18.5% aqueous Al(H2P04)3 solution 35.9% Sand 21%Sand 55 11.4% Circosol 304 (containing 2.5% oleic acid surfactant) 60 A napthenic Petroleum oil manufactured by the Sun Oil Company The percentages are percent of the ingredients by weight, based on the total combined weight of the components. The magnesium oxide had a surface area of 5.7 square meters per gram. The sand was Ottawa 65 16 GB 2 063 847 A 16 Silica Company's Banding Sand. This sand has round particles, 940/6 of which are in the size range of 74 to 210 microns, and 99% of which are smaller than 420 microns.

The composition of the aluminum phosphate solution, by weight, was 11.5% A1203,47.7% P205, and 40.8% H20.

The basic component (234 parts) was introduced into one compartment, and the acidic and aqueous 5 components (151 parts) into the other compartment, of a two-compartment frangible "chub" cartridge such as that described in U.S. Patents 3,795,081 and 3,861,522, the cartridge being made of poly ethylene terephthalate film. In the sealed compartmented cartridge, which was 41 centimeters long and 2.3 centimeters in diameter, the basic component and acidiclaqueous component were maintained separate from one another. The cartridge was cooled to 1 WC (to simulate the average temperature in a mine) and placed in a 41 -cm-long, 2.54 cm-in ner-d ia meter steel pipe having a rough wall (coarse threads) and a welded closure at one end (simulated drill hole). The pipe was held in an upright position in the vise of a Mayo machine with the closed end uppermost. The Mayo machine is one which is commonly used in mines to drill holes into mine ceilings and to install roof bolts for grouting. A 61 -cm- long reinforcing rod (bolt) having a diameter of 2 cm also was mounted in the Mayo machine. Both the pipe (drill hole) and the bolt were at 1 OOC. 15 Upon actuation of the machine, the rod was inserted into the cartridge with an upward motion at a speed of 6 meters per minute at 400 rpm. During insertion the bolt broke the polyethylene terephthalate film. After the bolt reached the closed end of the pipe, the bolt was spun for 35 seconds and completed mixing of the initially separated components.

Five minutes after the bolt installation had been completed, the pull strength of the hardened grout was 20 measured by applying an increasing force to the headed end of the bolt in a downward direction. The bolt broke at a load of 15.5 x 103 kg. Therefore, the grout supported a load of more than 378 kg per centimeter of anchoring length and exceeded the steel bolt in strength.

Example 25 25

The procedure described in Example 24 was repeated except that the magnesium oxide content of the grouting composition was 17%, sand 31.5% in basic, 15.3% in acidic, component, Circosol 12.7% and aluminum phosphate solution 23.6% and the magnesium oxide surface area was 10 square meters per gram.

The chub cartridge was 51 cm long, and contained 201 parts of the basic component and 128.5 parts of the acidiclaqueous component. In this case, after five minutes, the bolt broke at a load of 21.8 x 103 kg, the grout 30 having supported a load of more than 427 kg per centimeter of anchoring length.

4 - Example 26

A grouting composition was prepared which had the fol iowing components:

Basic Component AcidandAqueous Components MgO (43.62 parts) 74% aqueous solution of H3P04 (32.8 parts) 40 A1203-3H20 (23.44 parts) Sand (67.12 parts) Circosol 304 (32.12 parts) Polyethylene oxide (0.08 part) 45 Oleic Acid (0.82 part) The surface area of the magnesium oxide was 10 m21g. The sand was the same as that described in Example 24. The polyethylene oxide, which served as a thickener for phosphoric acid, was Polyox 301, having a 50 molecular weight of about 4,000,000.

The composition was loaded into a cartridge and tested as described in Example 24. The two-component cartridge contained 82.5 parts of the basic component and 199.5 parts of the acidiclaqueous component. The bolt was inserted into the cartridge at a speed of 3 meters per minute and a thrust of 454 kg. and mixed at a torque of 68 Newton meters. The total time required for bolt insertion and mixing was 25-27 seconds. In the 55 5-minute pull test, the bolt broke at a load of 15.2 x 103 kg, the grout having supported a load of more than 372 kg per centimeter of anchoring length.

GB 2 063 847 A 17 Example27

The effect of the surface area of magnesium oxide particles on the rate of hardening of a given grouting composition is shown in a series of experiments made with a composition containing 13% MgO, 7% A1203.3H20, 10% Circosol 304,23% H3P04 (74% aqueous solution), and 47% sand, the basic component containing the M90, A1203.3H20, Oil, and sand in an amount which was 20% of the total weight of the composition; and the acidic/aqueous component containing the H3P04 solution and the remainder of the sand. The composition was tested for 5-minute pull strength as described in Example 24.

Mg 0 Surface Area Pull Strength (M21g) (kglcm) 10 1.1 0 2.6 129 4.4 243 5.6 393 15 6.5 643 821 Thus, at the 13% M90 concentration level, grouts havine MgO surface areas below 4.4 m2/g required longer than 5 minutes to attain strength levels of 175 kg/cm. Above 10 m2/g, the setting rates were so high adequate 20 mixing of the components could not be accomplished.

Example 28

The following experiments show that a composition having a small surface area MgO and low setting rate can have its setting rate increased by increasing the MgO concentration. The experiments were carried out 25 on the composition described in Example 24 except thatthe MgO content was varied,the difference in the MgO content from that in Example 24 having been reflected in a proportionate decrease or increase in the sand content of the basic component described in Example 24.

5-Min Pull Strength 30 % Mgo (kglcm) 250 11.6 321 16 536 35 18 786 When the composition described in Example 24 was made with MgO having a surface area of 1.1 m21g, the 5-minute pull strength was 0 kg/cm, but at a MgO level of 25%, the composition had a 5-minute pull strength of 786 kg/cm.

Example29

A grouting composition was prepared which had the following components:

Acidic andAqueous 45 Basic Component Components 18.0% Mgo 18% aqueous M(H2P046 solution 35.6% Sand 20% Sand 50 8.4% Circosol A mixture of 48.75% Circosol 450,48.75% Circosol 4240, and 2.5% oleic acid.

The MgO was of the dead-burned type, having a surface area of 0.8 m21g, and a median particle size of 6 55 microns.

When cartridged and tested according to the procedure described in Example 24 (30 second mix time after installation; bolt insertion at 1000 kg thrust and mixing at 163 Newton meters torque), the 5 minute pull strength was 317 kg/cm.

18 GB 2 063 847 A 18 Example 30

The following grouting compositions were prepared:

A 8 5 Basic Component Basic Component 13% MgO (10 m21g) 15.4% MgO (10 m21g) 9, 10% Oil containing 2.5% 8.3% A1203.31-120 oleic acid - 10 27% Sand 11.8% Oil 23.7% Sand AcidiclAqueous Component AcidiclAqueous Component 15 23% aq. H3P04 (74%) 27% Sand 18.9% aq. H3P04 (74%) 21.9% Sand Both compositions were tested as described in Example 24, except that the pipe and bolt lengths were 12.7 20 cm. Mixing time after the bolt was in place was 30 seconds. With Composition A, the hardened grout, after five minutes, supported a load of up to 786 kg/cm and then failed. Composition B supported more than 857 kg/cm.

Examples 31-34 The effect of the water content of the grouting composition (orthe concentration of the Al(H2P0J3 solution) is shown in a series of experiments made with a composition containing 13% MgO, 10.4% Circosol, 57.9% sand, and 18.7% Al(H2P0J3 solution of different concentrations.

Al(H2P04)3 soIn. 5-Min Pull 30 Ex. %Al(H2P04)3 % H20 % Waterin Strength Grouting Compn. (kglcm) 31 71.6 28.4 5.3 714 32 69.7 30.3 5.7 393 35 33 67.3 32.7 6.1 321 34 47.6 52.4 9.8 71 1 19 GB 2 063 847 A 19 1 Examples 35-39 Five different compositions were prepared using an approximately 70% aqueous Al(H2P046 solution (11.2% A1203 and 46.8% P205) in the acid/aqueous component. In all cases, 61-cm-long, 2-cm-diameter bolts were installed into the grout as described in Example 24 and pull-tested 5-10 minutes after installation. Compositions, mole ratios, and pull strengths are tabulated below:

EX. Ex. Ex. Ex. Ex.

36 37 38 39 - 10 % Mgo 8.9 13.9 17.0 21 23 MgO Surface Area, M21g 20 15 10 -1 -1 is % oil - - 12.7 12.4 13.5 15 % Glycol 7.9 11.4 - - - % Sand 56.0 56.7 46.8 49.1 53.6 20 % AI (H2P04)3 - Soin. (70%) 27.2 18 23.6 17.5 10 Moles M90/P205 2.45 5.7 5.4 9.0 17.3 Pull Strength (kg/cm) 242 280 357 280 182 Circosol containing 2.5% oleic acid; in basic component In basic component.

Examples 40-45 Grouting compositions wherein oil was not present as a slush-forming liquid for the basic metal compound were prepared and tested as described in Example 24. Details of the compositions and test 35 results are given in the following table:

AcidiclWater Ex. Basic Component Component 5-Min. Pull Test Slush- OXY Forming Phosphorus MetalCompd. Sand Liquid Compd. Sand Conditions Results 16.4% MgO 29.4% aq. 43-cm cartridge 371 kg/cm 1 5M,/g) none none M(H2P043 54.2% weighing 347.9 g; soin. (a) 61 cm X 2cm bolt; 1000 kg thrust, 300 rpm, 6 meters/ min 41 12.8% M g 0 38.3% 8.5% 23.4% aq. 17.0% 13 cm X 2 cm 357 kg/cm (5.7 M2/g) water M(H2P04)3 bolt; mixed sol n. (b) 30 sec. at 400 rpm 42 18.3% MgO 12% 18.8% aq. 18.2% mixed 15 sec at 256 kg/cm (15 m/g) 32.7% glycol Al(H2P04N 320 rpm so In. (c) 43 11.9% MWOW2 28.7% 9.5% 25.0% aq. 25.0% 61 cm X 2 cm 259 kg/cm water Al(H2P04b bolt; 300 rpm, soin. (d) 7 meters/min 44 14.0% Mg(Offi2 28.0% 7.7% 23.7% aq. 24.4% mixed 15 sec 348 kg/cm glycol M(H2P046 in 10 min 2.1% soin. (d) water 10.10% Mgo 30.30% 9.09% 20.20% aq. 30.30% water (g) Mg (H2P042 soin. (f) % content is based on the total weight of the composition (a) A1203 11.5%, P205 47.7%, H20 40.8% (b) A1203 11.5%, P205 46%, H20 42.5% (c) A1203 10. 9%, P205 45.6% H20 43.5% (d) A1203 11.2%, P205 45.6%, H20 43.2% (e) A1203 11%, P205 47%, H20 34%, glycol 8% (f) 42.9 g MgO. 401.0 g H3P04 (85%),556. 1 g H20 per kg. soin. (g) Thickened with 1% polyacrylamide 1 l,' -1 11 G) to N) CD m W 00 Ph j 21 GB 2 063 847 A 21 In Example 45 the grout was evaluated by a shear strength measurement made by the following method:

A sample of the freshly mixed grout was placed on polyethyleneterephthalate film, and a stainless steel ring, 15.9 mm in diameter and 2.92 mm high, was placed on the grout.- A piece of polyethylene terephthalate film was placed over the ring, and the latter then was pressed evenly into the grout by means of a block of wood. The resulting "shear button" of the grout was placed on an Instron testing machine (conforming to 5 ASTM Method E4, Verification of Testing Machines), and tested 5 minutes after mixing) for shear strength by the method of ASTM D732. In this test, a plunger was brought down onto the grout at a rate of 12.7 mm per minute. The shear strength was calculated from the applied force to cause failure, according to the following equation:

shear strength = Force Specimen thickness X z X diam. of punch The measured shear strength was 90 kg/sq cm.

Example 46

A grouting composition was prepared containing 9.0% magnesium oxide (10 m/g), 14.1 % Circosol 450, 52.2% banding sand, 11.8% Al(H2P04)3 and 12.9% water. The M90/P205 molar ratio was 4. When tested as 20 described in Example 30, the hardened grout held a load of 572 kg/cm.

Control Experiments In contrast, a composition containing 8.7% magnesium oxide (10 m21g), 14.7% Circosol 450, 50.6% banding sand, 13.0% NH41-12P04, and 13.0% water (M90/P205 molar ratio = 4.4) held only 45 kg/cm. 25 When a bolt was embedded into a mixture of 8.7% MgO, 65.3% sand, 13.0% N1-14112P04, and 13.0% H20 and 25 tested as described in Example 30, the bolt was dislodged with less than 5 kg. force after 10 minutes.

Example 47 The following composition was prepared: 30 13% MgO (surface area 18.4 m2/g) 56.4% banding sand 12.0% ethylene glycol (in basic component) 18.6% AI (H2P0J3 solution (10.5% A1203,42% P205) This grout, tested as described in Example 30, had a pull strength of 672 kg/cm in 5 minutes.

Claims

1. A grouting system for use in a hole in combination with a reinforcing member wherein a hardened grout is formed around the reinforcing member in the hole by the reaction of the mixed components of a hardenable inorganic grouting composition, thereby anchoring the reinforcing member in the hole, characterized in that the grouting composition is inorganic and comprises (a) an acidic reactive component comprising at least one acidic oxy phosphorus compound selected from phosphoric acids, anhydrides of phosphoric acids, and salts of phosphoric acids with multivalent metal cations; (b) a basic reactive component comprising at least one particulate basic metal compound of a Group 11 or 45 Group Ill metal capable of reacting with the oxy phosphorus compound(s) in the presence of water to form a monolithic solid; and (c) an aqueous component; the components being present in or outside a hole in a separated condition such that any substantial So hardening reaction between the acidic and basic components is prevented, and when present outside the 50 hole being adapted to be delivered into the hole separately or in a freshly combined condition; the basic metal compound(s) having a particle surface area of up to about 40 square meters per gram and constituting about from 5 to 35 percent of the total weight of the grouting composition, with the proviso that when the particles of the basic metal compound(s) have a surface area of less than 1 square meter per gram, more than about 95 percent of the particles pass through a 200 mesh screen; the ratio of the moles of the basic 55 metal compound(s) to the moles of phosphorus pentoxide on which the oxy phosphorus compound(s) are based being in the range of about from 2/1 to 1711; the amount of water present in the composition constituting about from 3 to 20 percent of the total weight of the grouting composition; a particulate aggregate being present in the composition in an amount such as to constitute about from 30 to 70 percent of the total weight of the composition; and the components, when mixed reacting without the application of 60 heat thereto to form a hardened grout having a pull strength of at least about 175 kilograms per centimeter of anchoring length within an hour.

2. A grouting system as claimed in Claim 1 wherein the aqueous component and acidic reactive component are combined and maintained separate from the basic reactive component.

3. A grouting system as claimed in Claim 2 wherein the combination of aqueous and acidic reactive 22 GB 2 063 847 A 22 components is an aqueous solution of phosphoric acid or of an acid salt of phosphoric acid with a multivalent metal cation.

4. A grouting system as claimed in Claim 2 wherein the basic metal compound is selected from magnesium oxide, aluminium oxide, magnesium hydroxide, ferric hydroxide, aluminium hydroxide,

5 magnesium silicate, magnesium aluminate and calcium aluminate, 5. A grouting system as claimed in anyone of Claims 1 to 4 wherein the basic metal compound is in a substantially dry state.

6. A grouting system as claimed in anyone of Claims 1 to 4 wherein the basic reactive component is in the form of a slush with a liquid which is substantially non-reactive with the basic metal compound(s).

7. A grouting system as claimed in Claim 1, 2,3,5 or 6 wherein the basic metal compound is magnesium 10 oxide or hydroxide.

8. A grouting system as claimed in Claim 7 wherein the basic reactive component additionally contains aluminium oxide.

9. A grouting system as claimed in Claim 2 wherein the solution is a solution of an acidic aluminium phosphate.

10. A grouting system as claimed in Claim 9 wherein the solution is supersatu rated.

11. A grouting system as claimed in Claim 6 characterised in that the substantially non-reactive liquid is a hydrocarbon.

12. A grouting system as claimed in Claim 6 wherein the substantially nonreactive liquid is a polyol.

13. A grouting system as claimed in Claim 6 wherein the substantially nonreactive liquid is water.

14. A grouting system as claimed in Claim 2 wherein the combined aqueous and acidic reactive components are maintained in one compartment and the basic reactive component in another compartment of a compartmented frangible package.

15. A grouting system for use in a hole in combination with a reinforcing member wherein a hardened grout is formed around the reinforcing member in the hole by the reaction of the mixed components of a 25 hardenable inorganic grouting composition, thereby anchoring the reinforcing member in the hole, wherein the grouting composition is inorganic and comprises an aqueous solution of phosphoric acid or of an acidic aluminium phosphate, magnesium oxide or hydroxide separated from the aqueous solution, and sand; the magnesium oxide or hydroxide having a particle surface area of up to about 30 square meters per gram and constituting about from 5 to 35 percent of the total weight of the grouting composition; the ratio of the moles 30 of the magnesium oxide or hydroxide to the moles of phosphorus pentoxide on which the phosphoric acid or phosphate is based being in the range of about from 211 to 17/1; the amount of water present in the composition constituting about from 3 to 20 percent of the total weight of the grouting composition; the sand being present in the composition in an amount such as to constitute about from 30 to 70 percent of the total weight of the composition; and the magnesium oxide or hydroxide and phosphoric acid or phosphate, 35 when mixed, reacting without the application of heat thereto to form a hardened grout having a pull strength of at least about 175 kilograms per centimeter of anchoring length within ten minutes.

16. A method of fixing a reinforcing member in a hole in a rock formation which comprises (a) delivering into the hole in controlled amounts the components of a hardenable grouting composition having as a first component i) an acidic reactive component comprising at least one acidic oxy phosphorus compound selected from phosphoric acids, anhydrides of phosphoric acids and salts of phosphoric acids with multivalent metal cations; ii) a basic reactive component comprising at least one particulate basic metal compound of a Group 11 or Group Ill metal capable of reacting with the oxy phosphorus compound(s) in the presence of water to form a 45 hardened solid mass; and iii) an aqueous component; and (b) introducing a reinforcing member into the hole before any substantial hardening of the composition has occurred, the components being delivered to the hole separately or in a freshly mixed condition so as to 50 avoid premature hardening of the components prior to introducing the reinforcing member.

17. A method according to claim 16 wherein the composition has two components, the aqueous component being combined with the acidic component.

A t z Printed for Her Majesty's Stationery Office. by Croydon Printing Company Limited, Croydon, Surrey, 1981, Published by The Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.