KR20150112497A - Quick-setting mortar composition for compaction grouting process - Google Patents

Abstract

The present invention relates to a quick-setting mortar composition for a compaction grouting process using a low fluidity mortar having a low slump as an injection material during a grouting process enhancing a base for enhancing weak ground or preventing subsidence of structures on the weak ground, or for assuring safety of ground and underground structures, buildings, etc. having safety risk by previous subsidence. The quick-setting mortar composition for a compaction grouting process according to the present invention includes 50 parts by weight of clay silty soil having particle size distribution of 0.02-0.15 mm as fine aggregates, and 50 parts by weight of a rock powder having particle size distribution of 0.08-10 mm as coarse aggregates, and includes 10-30 parts by weight of a blast furnace slag cement, 2-6 parts by weight of calcium sulfur aluminate having contents of aluminum oxide 50% or more, and 2-6 parts by weight of petro coke desulfurized plaster for 100 parts by weight of the aggregates.

Description

 TECHNICAL FIELD [0001] The present invention relates to a quick-setting mortar composition for compaction grouting,

The present invention relates to a grouting method in which a foundation is reinforced in order to reinforce a soft ground or to prevent the settlement of a structure on a soft ground or to secure the safety of ground and underground structures and fixtures that have been already settled and are threatened with safety, More particularly, the present invention relates to a low-speed mortar composition for use in low-flowable mortar as a filling material, and more particularly, to a low-flow mortar composition for a compaction grouting method, It accelerates the amorphous materials such as air shortening and high calcium fly ash, enhances the strength, and compensates the shrinkage characteristics of the cement mortar by using the absorption, exothermic reaction and volumetric expansion action of CaO contained in the high calcium fly ash Significantly improve the performance of soft soil improvement To a fast-curing mortar composition for compaction grouting.

In general, grouting works to improve the soft ground by filling the material, such as injecting chemical solution injecting cement milk and chemical, locally pouring aggregate piling method for buying aggregate such as gravel on excavation ground, compaction filling low slump mortar And compaction grouting method. Compaction grouting method which is evaluated to be most resistant to vertical pressure and horizontal pressure and dynamic load is applied to many sites.

The construction of the compaction grouting method is a method of drawing a low-flow mortar using a high-pressure pump immediately after piercing a hole with a perforator to a predetermined depth in a ground to be improved, and cement is used as a binder in a soft ground, It is a method of filling low-flowable mortar mixed with water by using rosy grit fine particles and stones.

However, in the case of the above-mentioned cement, since the predetermined strength is exhibited after 28 days after curing, the construction period may be delayed.

Disclosure of the Invention The present invention has been conceived in order to solve the above-mentioned problems. It is an object of the present invention to provide a method for producing a high-calcium fly ash by shortening the air by applying a blast furnace slag cement and CSA (Calcium Sulfur Aluminate) Strength, and at the same time, the absorption of CaO contained in the high-calcium fly ash, the exothermic reaction and the volumetric expansion action are used to reduce the loss of the cement paste caused by the groundwater that may exist between the perforation hole and the mortar, The present invention provides a fast-curing type mortar composition for compaction grouting, wherein the friction force at the main surface is greatly improved as compared with the mortar using only conventional cement.

In order to solve the above technical problems, a fast-curing mortar composition for compaction grouting according to the present invention comprises 50 parts by weight of silt and 50 parts by weight of silt in an aggregate of 100 parts by weight of the aggregate, 10 to 30 parts by weight of blast furnace slag cement, 2 to 6 parts by weight of CSA (Calcium Sulfur Aluminate) having an aluminum oxide content of 50% or more, and 2 to 6 parts by weight of Petro coke desulfurization gypsum.

It is preferable that the visco-silty grit soil is fine aggregate having a particle size distribution of 0.02 mm to 0.15 mm. The above-mentioned abrasive is preferably a coarse aggregate having a particle size distribution of 0.08 mm to 10 mm.

It is also preferred that an expander is further included.

Also, the expanding material may be a desulfurization-type coal combustion incineration residue, a biomass incineration residue, a paper sludge incineration residue, an RDF incineration residue, an RPF incineration residue, a converter slag dust, a quick lime, and a light dolomite with a calcium oxide (CaO) content of 20% And more preferably at least one selected from the group consisting of

Preferably, the expandable material is incorporated in an amount of 2 to 6 parts by weight based on 100 parts by weight of the aggregate.

It is also preferable that water is further included as the blending water. This water is not particularly limited as long as it does not contain salt. For example, it is preferable that at least one member selected from the group consisting of groundwater containing no salt, surface water, tap water, and industrial water is desirable.

The water is preferably mixed with 2 to 3 parts by weight based on 100 parts by weight of the aggregate.

According to the present invention, by using the blast furnace slag cement and CSA (Calcium Sulfur Aluminate), which are a binder of mortar, it is possible to shorten the air by imparting a quick hardening property, activate an amorphous material such as high calcium fly ash to exhibit strength, By using absorption of large amount of CaO, exothermic reaction and volumetric expansion, loss of cement paste caused by groundwater, which may exist between perforation hole and mortar, is reduced and the end bearing capacity and main surface friction force of grouting mortar are reduced to mortar The present invention provides a fast-curing mortar composition for compaction grouting,

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a part or a combination thereof is described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

It is to be understood that the invention is not to be limited to the specific forms disclosed, but is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Hereinafter, a fast-curing mortar composition for a compaction grouting method according to the present invention will be described in detail.

First, the constituent components and the action of a fast-curing mortar composition for a compaction grouting method according to the present invention will be described.

The fast curing type mortar composition for compaction grouting according to the present invention is characterized in that 50 parts by weight of stone powder is composed of aggregate in 50 parts by weight of visco-soil-silty soil, 10 to 30 parts by weight of blast furnace slag cement 2 to 6 parts by weight of CSA (Calcium Sulfur Aluminate) having an aluminum oxide content of 50% or more, and 2 to 6 parts by weight of Petro coke desulfurization gypsum.

It is preferable that the visco-silty grit soil is fine aggregate having a particle size distribution of 0.02 mm to 0.15 mm. The above-mentioned abrasive is preferably a coarse aggregate having a particle size distribution of 0.08 mm to 10 mm.

Further, it is preferable that an expansion material is further included to improve the friction force of the main surface of the mortar composition through volume expansion.

Also, the expanding material may be a desulfurization-type coal combustion incineration residue, a biomass incineration residue, a paper sludge incineration residue, an RDF incineration residue, an RPF incineration residue, a converter slag dust, a quick lime, and a light dolomite with a calcium oxide (CaO) content of 20% And more preferably at least one selected from the group consisting of

It is preferable that the expansion material is incorporated in an amount of 2 to 6 parts by weight, preferably 2 to 3 parts by weight, based on 100 parts by weight of the aggregate.

In addition, an expanding material having a calcium oxide (CaO) content of 20% or more reacts with water to be absorbed, exothermic, and expanded to become calcium hydroxide. The reaction formula is as follows.

CaO + H2O- > Ca (OH) 2 + 15.6 kcal mol-1

Although the coal ash discharged from a thermal power plant having a separate desulfurization apparatus is recycled as a concrete admixture material with a calcium oxide (CaO) content of 5% or less, coal ash and incineration residues containing a large amount of calcium oxide as described above, It can not be used as a concrete admixture because of its heat and expansion characteristics.

Therefore, the present invention utilizes incineration residues, which can not normally be utilized as a concrete admixture, as an expansion material.

The blast furnace slag cement used as the main material of the binder in the present invention is a product manufactured according to Korean Industrial Standards (KS) by adding fine powder of blast furnace slag and a small amount of gypsum to the first type cement, Is excellent. This blast furnace slag cement is a fine aggregate composed of 10 parts by weight of 100 parts by weight of an aggregate composed of 50 parts by weight of aggregate having a particle size distribution of 0.02 mm to 0.15 mm and 50 parts by weight of a stone powder having a particle size distribution of 0.08 to 10 mm as coarse aggregate, To 30 parts by weight, and more preferably 10 to 20 parts by weight. When the amount of the binder is less than 10 parts by weight, the amount of the binder is too small to exhibit the predetermined strength. When the amount of the binder exceeds 30 parts by weight, the amount of the binder is excessive.

The CSA (Calcium Sulfur Aluminate) generally referred to as ultra rapid cement or alumina cement is preferably contained in an amount of 2 to 6 parts by weight, more preferably 2 to 3 parts by weight, based on 100 parts by weight of the aggregate. If the amount is less than 2 parts by weight, the curing of the mortar injection material is insufficient for rapid curing. If the amount is 6 parts by weight or more, the curing time is shortened so that the mortar hardens before a sufficient time for the construction.

Also, the Petro Causus desulfurization gypsum reacts with slag in blast furnace slag cement in the early stage of the reaction to produce a large amount of etyne wite, and activates slag and coal as an amorphous material over time to act as a stimulant to express strength Because it is generated from incinerator as waste, it is superior in economy compared to phosphate gypsum which has to undergo dehydration process by natural prime minerals and sintering which have equivalent performance.

Desirably, the Petro Cokes desulfurization gypsum is contained in an amount of 2 to 6 parts by weight, more preferably 2 to 4 parts by weight, based on 100 parts by weight of the aggregate. If the amount is less than 2 parts by weight, the effect of the alkali / sulfate complex irritant containing the CaO component and the gypsum component at the same time is insufficient. If the amount is more than 6 parts by weight, there is a surplus amount that does not react with the slag and the coal material, have.

Further, it is preferable that an expansion material is further included to improve the frictional force of the main surface of the injection mortar.

The expansion material is composed of an in-furnace desulfurization-type coal combustion incineration residue, a biomass incineration residue, a paper sludge incineration residue, an RDF incineration residue, an RPF incineration residue, a converter slag dust, a quicklime and a light dolomite having a calcium oxide (CaO) content of 20% And 2 to 6 parts by weight, preferably 2 to 4 parts by weight, based on 100 parts by weight of the aggregate.

If the mixing amount of the expanding agent is less than 2 parts by weight, the expansion effect is insufficient for improving the frictional force of the main surface of the embedded pile. If the mixing amount exceeds 6 parts by weight, the expansion effect is increased, but the strength of the cured material is insufficient .

In addition, water is included as a blending water for smoothly mixing the above materials, inducing a hydration reaction of the binder, and maintaining a predetermined mortar kneader. This water is not particularly limited as long as it is water containing no salt. For example, it is preferable that at least one member selected from the group consisting of groundwater containing no salt, surface water, tap water, and industrial water is desirable.

It is also preferred that the water is incorporated in such an amount that the mortar slump according to KS F 2402 (slump test method of concrete) is 50 to 70 mm. For example, the water is mixed with 2 to 3 parts by weight with respect to 100 parts by weight of the aggregate. If the amount of water is less than 50 mm, the kneading of the mortar becomes too much so that it is not sufficiently mixed in the mortar manufacturing process and the possibility of sticking during the process is increased. If the slump is over 70 mm, The kneading agent becomes too thick and the water cement ratio becomes high and the predetermined strength can not be developed.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described. The following examples are intended to illustrate the invention and should not be construed as limiting the scope of the invention.

Example

First, according to the compaction grouting method standard specification, as fine aggregate, 50 weight parts of silt earth silt having a particle size distribution of 0.02 mm to 0.15 mm were mixed with 50 weight parts of aggregate having a particle size distribution of 0.08 to 10 mm as coarse aggregate , 11 parts by weight of blast furnace slag cement, 3 parts by weight of CSA (Calcium Sulfur Aluminate) having an aluminum oxide content of 50% or more, 3 parts by weight of PetroCouks desulfurization gypsum, 3 parts by weight of an expansion agent and 2.5 parts by weight Were mixed homogeneously with a forced mixer to prepare a quick-setting mortar mixture.

The slump test was carried out using the samples prepared in the following, and the specimens for measuring the compressive strength were prepared and the compressive strengths were measured at each ages.

Comparative Example (OPC)

First, according to the compaction grouting method standard specification, as fine aggregate, 50 weight parts of silt earth silt having a particle size distribution of 0.02 mm to 0.15 mm were mixed with 50 weight parts of aggregate having a particle size distribution of 0.08 to 10 mm as coarse aggregate 20 parts by weight of a type 1 portland cement and 2.5 parts by weight of a compounding agent were homogeneously mixed with 100 parts by weight of the aggregate by a forced mixer to prepare a mortar mixture.

The slump test was carried out using the samples prepared in the following, and the specimens for measuring the compressive strength were prepared and the compressive strengths were measured at each ages.

Performance test method and result of injection mortar for compaction grouting method

As shown in Table 1 below, the slump test was conducted by KS F 2402 (slump test method of concrete) and the compressive strength test was conducted by KS F 2405 (compressive strength test method of concrete).

Experiment Way designation Slump flow KS F 2402 Test method of concrete slump Compressive strength KS F 2405 Test method of compressive strength of concrete Degree of material separation Visual inspection Volume change Visual inspection

(1) Results of the slump test

The results of the measurement of the slump of the examples and comparative examples are shown in Table 2. The slump of the mortar injection material of the example was slightly lower although the weight of the unit binder material and the weight of the compounding material of the examples and the comparative example and the weight of the aggregate were the same. This can be interpreted as a result of the increase of the unit powder amount of the binder containing the ash, which is lower in mass than the cement, and the petroleum coke desulfurization gypsum. Further, it is judged that the fluidity is lowered due to absorption, exothermic and expansion action when the calcium oxide component in the expanding material is contacted with water because the expanding material is further mixed.

Results of slump and compressive strength measurements division Slump (mm) Compressive strength (MPa) 3 days 7 days a year 28 days old Example 55 17.2 20.7 29.4 Comparative Example 70 12.3 19.8 23.2

(2) Unconfined compressive strength test performance

Table 2 shows the results of uniaxial compressive strength tests of Examples and Comparative Examples.

As shown in Table 2, the initial strength was significantly higher than that of the first-grade cement, which is a comparative example, and this is an effect due to incorporation of CSA (Calcium Sulfur Aluminate). Also, the strength at 7 days and 28 days was also superior to that of the first grade cement, which is a comparative example. It is considered that slag in blast furnace slag cement and amorphous material of expansion material continuously produce hydrate by the sulfate and alkali stimulation of petro coke.

As can be seen from the above table, when the same amount of the binder material was used, the compressive strength of the example was excellent. As a result, when the same amount of binder material was used, it was estimated that air shortening was possible. The same strength as that of the first type cement can be exhibited, which is considered to be an economical construction guarantee.

(3) Other

In all of the examples and comparative examples, no material separation occurred after mixing the mortar, and the workability of the site was ensured. By visually observing the volume change before capping, the compressive strength specimen was prepared, Although the volume of the example was increased by compensating for the amount of shrinkage caused by the expandability, it was visually confirmed that the volume shrinkage occurred in the comparative example.

Claims (7)

And 50 to 50 parts by weight of stonite are mixed with 100 parts by weight of the aggregate, 10 to 30 parts by weight of blast furnace slag cement, 2 to 6 parts of CSA (Calcium Sulfur Aluminate) having an aluminum oxide content of 50% And 2 to 6 parts by weight of petrocomposite gypsum desulfurization gypsum. The method according to claim 1,
Wherein the viscous silty earth is a fine aggregate having a particle size distribution of 0.02 mm to 0.15 mm and the granite is a coarse aggregate having a particle size distribution of 0.08 mm to 10 mm. The method according to claim 1,
≪ / RTI > wherein the composition further comprises an expanding agent. The method of claim 3,
The expansion material is composed of an in-furnace desulfurization type coal combustion incineration ash with a calcium oxide (CaO) content of 20% or more, biomass incineration residues, paper sludge incineration residues, RDF incineration residues, RPF incineration residues, converter slag residues, quicklime and light dolomite Wherein the fast grouting mortar composition is at least one selected from the group consisting of polypropylene and polypropylene. The method of claim 3,
Wherein the expandable material is incorporated in an amount of 2 to 6 parts by weight based on 100 parts by weight of the aggregate. The method according to claim 1,
Wherein the composition further comprises water as a blending water. The method according to claim 6,
Wherein the water is incorporated in an amount such that the slump of the mortar according to KS F 2402 (slump test method of concrete) is 50 to 70 mm.