RU2696747C1 - Composition for filling expansion joints and method of its preparation - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: group of inventions relates to the field of construction and repair of road surfaces and can be used in the construction of expansion joints of closed type with macadam-mastic filling. Composition for filling pavement joints of road pavements includes, wt%: gabbro-diabase stone chips 40.0–90.0, microballs and/or microspheres from radar absorbent material, produced by plasma technology, 0.5–50.0, bitumen-polymer mastic 5.0–40.0, note here that said chips, microballs and/or microspheres are pre-dried and simultaneously hydrophobisated with organosilicon water-repellent in amount of 0.1–5.0 % of processed material weight with application of microwave radiation. Invention also relates to a method for preparing said composition. Invention is developed in dependent claims.

EFFECT: improving reliability and serviceability of road surface joints of road surfaces due to use of composition for filling seams, having high heat resistance, frost resistance, radiation resistance, water resistance and vibration resistance.

5 cl, 1 tbl

Description

The invention relates to the field of construction and repair of road surfaces and can find application in the construction of closed expansion joints with crushed stone and mastic filling.

The expansion joint is designed to reduce loads on structural elements in places of possible deformations arising from fluctuations in air temperature, seismic phenomena, uneven subsidence of the soil and other influences that can cause dangerous intrinsic loads that reduce the bearing capacity of structures.

As the main species characteristic of expansion joints, dividing structural solutions into types of construction, a method of overlapping the gap between the ends of the span or the end of the span and the support is adopted. According to the method of overlapping the gap KDSh are divided into the following types:

- open - the gap (seam) is open and water, dirt and various objects freely enter the space between the ends of the spans (such structures were not used on bridge structures of the roads of the Russian Federation due to the need for daily cleaning);

- closed - the gap is closed from above (at the level of pavement or pavement), and the pavement does not have a gap above the gap;

- filled - the coating and all layers of clothes have a gap above the gap, filled, as a rule, with an elastic element (rubber, mastic ...), due to the deformation of which the movements of the ends of the span are compensated;

- closed - the gap between the ends of the spans is blocked by any element (sheet, plate) that changes position (without opening the gap) when the ends of the spans are moved;

Ultimate displacements are the main characteristic of the design of the expansion joint, along which a preliminary selection of the possible design of the expansion joint, possible for a particular structure, is carried out.

The most preferred design of the expansion joint for pavement is a closed type design.

Expansion joints should have the following properties:

- elasticity over a wide temperature range of -50 - + 50 ° С (i.e. heat resistance, frost resistance);

- resistance to ultraviolet (radiation resistance);

- have a long service life without noticeable degradation;

- be waterproof or hydrophobic during the life of the product;

- be cheap enough, that is, made from local raw materials and should not contain expensive or difficult components in the production of the seam;

- the application process should also be cheap and simple technologically;

- must have adhesion to the surrounding asphalt, metal, stone.

Various technical solutions are known in the art. For example, the design of the expansion joint of the roadway of the bridge according to the patent of the Russian Federation No. 2144076, priority 23.08.1999, published on 04.10.2001, is known.

A well-known technical solution relates to the construction of the carriageway of road bridges and overpasses in the interface zone of superstructures, superstructures with abutments, as well as the conjugation of approaching sections of embankments with a transition plate. The design contains a deformation seam of the carriageway of the bridge with gravel filling. New in design is that the crushed stone filling is enclosed in a cage made of roving fiberglass, on top of which a steel-fiber-reinforced concrete distribution plate is laid. Crushed stone in the holder can be impregnated with a hydrophobic elastic material. The disadvantages of the known technical solutions are limited mobility of crushed stone during the deformation of the seam due to its shape and structure, lack of technology for economical, fast and reliable hydrophobization of crushed stone.

Also known is the technical solution for the construction of a closed expansion joint, set forth in the current model project of Soyuzdorniya series 3.503 1-101, 1992. “Insulation of the roadway, overlapping expansion joints of reinforced concrete spans up to 33 m in length of road bridges and overpasses”, p. 30. The main structural elements are a metal compensator, an anchor rod, filling mastic, porous filler, a separating gasket from two layers of roofing felt, a 200 mm wide SPAP fiberglass, a 300 mm wide SPAP fiberglass mm

These types of seams are widespread due to such advantages as: extreme simplicity of the device; low cost; minimum parts, lack of complex components, low material consumption; flat surface, good grip on the car wheel; immunity to damage by snow blowers. However, it has disadvantages. The main detected defect of this type of joints, which determines their serviceability, is a leakage that occurs due to the formation of cracks in the structure due to the low deformability of ordinary asphalt concrete, especially at low temperatures. Stagnant water in the weld structure leads to accelerated degradation of materials.

Closest to the proposed set of essential features is the technical solution given in the industry road methodological document “DEFORMATION SEAMS OF BRIDGE STRUCTURES ON ROADS” (ODM 218.2.025-2012) and selected as a prototype. A longitudinal niche is disassembled along the axis of the seam in the laid asphalt concrete pavement according to the design dimensions of the construction of the future expansion joint. The side walls of the niche should be strong and parallel to each other. The base of the seam niche and the surface of the expansion joint should be taken parallel. The gap of the expansion joint is filled with sealing material and spilled with mastic, on which an overlapping steel sheet is laid on top. To fill the seam niches, cubic single-fraction gravel from natural rocks is used (basalt, gabbro, diabase and granite), a grade of strength more than 120 MPa (1200 kg / sq. Cm). Crushed stone fraction - 15-20 mm. Crushed stone is prepared in accordance with GOST 8267, it is washed, sieved, sorted and packaged in bags. Before laying in the seam ’sill, gravel is additionally passed through a control sieve with openings No. 15 and No. 20; and heated in a mixer with hot compressed air or in special fryers to a temperature of 150 ° C. For the surface layer of the seam, granite signboards with a grain size of 5 mm are used. As a binder for processing crushed stone, polymer-bitumen mastic is used, heated to (190 ± 20) ° С. Surface treatment of the weld zone is carried out by applying mastic to the last layer of crushed stone, followed by sprinkling a layer of fine crushed stone with a fraction of up to 5 mm.

The disadvantages of the prototype are: lack of reliability of the design and low serviceability, as well as low maintainability. The presence of separate operations of heating gravel with subsequent impregnation with mastic does not guarantee complete hydrophobization of gravel, the presence of hard gravel rubble requires a significant amount of mastic (sealing - as described in the patent, but not providing sufficient mobility of gravel), which reduces the cost-effectiveness of the expansion joint.

The technical problem that currently exists is insufficient reliability, low serviceability, poor waterproofing (lack of hydrophobicity), and low maintainability of expansion joints of road surfaces, which reduces road safety and often requires expensive road repair work.

The technical result of the invention is to increase the reliability and increase the serviceability of the expansion joints of road surfaces through the use of a composition for filling joints with high heat resistance, frost resistance, radiation resistance, water resistance and vibration resistance. This becomes possible due to the use of gabbro-diabase gravel in the composition for filling the expansion joints, treated with water-based organosilicon hydrophobizing agents together with microspheres / microspheres. At the same time, it becomes possible to heat the composition of the HF / microwave radiation during installation and repair, which greatly simplifies the production technology.

Thus, the technical result is achieved due to the fact that in the composition for filling expansion joints, consisting of a chemically inert filler, including crushed stone of various fractional composition, and bitumen-polymer mastic, it is proposed to use gabbro-diabase crushed stone as crushed stone in an inert composition the filler along with crushed stone to introduce microspheres and / or microspheres of radar absorbing material made by plasma technology. Moreover, crushed stone, microspheres and / or microspheres are pre-dried and simultaneously hydrophobized with organosilicon water repellents in an amount of 0.1-5.0% by weight of the processed material using microwave radiation. Moreover, the ratio of components in the composition is as follows, wt.%:

Crushed stone - 40.0-90.0%

Bitumen-polymer mastic - 5.0-40.0%

Microspheres and / or microspheres - 0.5-50.0%

Additional differences in composition are:

- as crushed stone of gabbro-diabase rocks crushed stone with a size of fractions of 2.5 - 15.0 mm was used,

As gabbro-diabase rocks, rocks from the Golodai Gora deposit, the Uchalinskoye deposit (Bashkortostan), or other rocks with similar characteristics are used. As bitumen-polymer mastic applied products manufactured in accordance with the requirements of GOST 32870-2014, or ND factories.

- as microspheres and / or microspheres of radio-absorbing materials produced by plasma technology, microspheres of gabbro-diabase, pomegranate, aegirine, nickel slag or a mixture thereof are used.

Also, the technical result is achieved due to the fact that in the method of preparing the composition according to claim 1 for filling expansion joints, including mixing an inert filler and bitumen-polymer mastic, it is proposed to mix the inert filler in the composition of crushed stone and microspheres / microspheres from the radar absorbing material with organosilicon hydrophobizing agents, preferably water-based, in an amount of 0.1-5.0% by weight of the processed material, dried using microwave radiation and then introduce iku continuously stirring.

The proposed composition has all the necessary properties that are presented to the expansion joints of road surfaces, namely, it is elastic in a wide temperature range of -50 - + 50 ° C, has radiation resistance, has a long service life without noticeable degradation, waterproof, fairly cheap, has adhesion to asphalt concrete pavement. The process of applying it is also quite cheap and simple. In addition, the proposed composition has high strength, wear resistance in operating conditions. It also has good maintainability, vibration resistance, which is higher than that of the environment, and sound absorption, vibration damping and shock resistance, the ability to self-repair and self-heal when exposed to temperature. All these properties make the proposed composition much better than the known world samples.

When microbeads from radar absorbing materials were introduced into the composition to fill the expansion joints of pavements, their high adhesion to various bitumen compositions was suddenly discovered (1-60% by volume in the mastics was introduced). Since the microspheres have microhardness from 3 to 8 GPa, the black color that protects the mastic from ultraviolet radiation, zero water absorption, have an ideal spherical shape that prevents the development of cracks in the volume of the mastic at low temperatures, and also have a unique ability to self-heal when temperature changes (when heated) , and the ability of vibration damping or sound absorption (since the microspheres are glass), the compositions with microspheres passed many years of testing outdoors when adhering to asphalt (more than 3 years) b Without traces of degradation.

The high deformability of individual samples with spheroidized fillers made it possible to make the compositions high-strength, but fluid when the load is applied slowly (during the day). Thus, the sample is durable and resistant to impact, after a long time it took the form in which it was installed, that is, it had the fluidity of bitumen.

Preferred in the manufacture of expansion joints is the following sequence of operations. The prepared gabbro-diabase crushed stone is mixed with microspheres, the mixture is heated with microwave radiation and at the same time its hybridization. This mixture is easily transported and stored for a long time without loss of quality. Then, preheated mastic is added to the mixture with constant stirring and additional heating of microwave radiation. Bringing the composition to a plastic state, it is filled with expansion joints, followed by compaction by tamping or rolling of the expansion joint.

A significant difference of the proposed method of preparing the composition for filling the expansion joints is the presence of a hydrophobization process of the filler in the presence of RF / microwave radiation. Fillers of the composition are dried (dehydrated) by microwave radiation, including glass beads, with evaporation of residual water (including from the surface of the beads). At the same time introduced into the gravel, which is mixed with microspheres, the organosilicon water-repellent agent in the form of a solution, evaporates under the influence of microwave, treats the surface of the fillers with its vapor. The active agents on the fillers are the residual water vapor together with the vapor of the water repellent solution. The process occurs at a temperature of 100-125 ° C. Drying is combined with hydrophobization with free ventilation (steam removal) after a preliminary kneading of a portion of the hydrophobizer solution. The operation differs from the classical drying of fillers, in which, after applying a water repellent on their surface, the filler is blown with heat flow for a long time (from several hours to a day). The properties of the microspheres - flowability, hydrophobicity compared with non-hydrophobized are dramatically improved. Filler - gabbro diabase completely loses water, becoming hydrophobic. The organosilicon water-repellent agent is selected here only as the material most resistant to negative temperatures in construction.

Since these fillers are radar absorbing materials in the microwave range, i.e. are heated in the microwave field, and heating and vaporization (and steam removal) occur in the medium of water vapor - an effective microwave absorber in the 2.4 GHz band, on which the vast majority of magnetrons (microwave ovens) operate, then the process is economically and with high efficiency.

The time of hydrophobization is also significantly reduced from a day to several minutes. For example, when testing gabbroid rocks (1 kg of screening 1-10 mm), crushed stone with microspheres was dehydrated from natural moisture in the presence of 10 g of a water-based organosilicon hydrophobizer for 4 minutes at a power of 800 watts. A liquid-based organosilicon liquid-based hydrophobizer was used of the Hydroeffect-2.1 brand. Similar water repellents (in composition) showed a close result.

Hydrophobization also provides a long (more than 5-7 years) service life of the composition without the damage that occurs due to moisture and freezing. The composition prepared with the addition of microspheres from gabbro-diabase, pomegranate, aegirine, nickel slag, other iron oxide glasses, and other oxides that absorb electromagnetic radiation, or their mixtures subjected to hydrophobization in this way, showed increased water resistance compared to control samples without volumetric hydrophobization of fillers .

Separately, it is necessary to dwell on the problem of being in the composition for filling the expansion joints of screenings and rubble. In the presence of the hydrophobization proposed in the invention by organosilicon liquids using microwave radiation combined with dehydration, the most effective materials were gabbroid rocks (for example, the Golodai Gora deposit). But when mixing screenings and crushed stone with a certain (adjustable) number of microspheres, a more mobile, less rigid frame of the expansion joint is obtained. Microballs - even stronger and harder than gabbro, are an additional lubricant in the composition, actually dusting larger particles of screening, gravel, which allows the joint to acquire self-healing ability. Microballs, like small balls of bearings, work in expansion joints for rolling friction, in contrast to sliding friction in traditional fillers, and when chemically inert they do not oxidize the binder.

When applying expansion joints to metal surfaces, such as bridges, the use of radar absorbing materials in combination with high-frequency / microwave heating of the expansion joint material gives a positive effect of reflection from the radiation metal surface and the expansion joint material is selectively heated in the same way as in a microwave oven by repeated reflection . Such heating is much more economical than traditional thermal (infrared). Therefore, it is based on the action of all microwave emitters.

The usual crushed stone component of asphalt concrete contains a certain amount of water and it is traditionally heated before kneading with a binder, including to remove water. In this invention, the operation of heating the filler is combined with hydrophobization with a solution of organosilicon liquid, preferably using microwave heating, which allows to accelerate the process of hydrophobization from day to minutes with the complete removal of water from the crushed stone filler (for example, screening gabbroid rocks). The final (hydrophobized) product does not contain water and is able to resist moisture for a long time (years). Moreover, after the hydrophobization operation, it is covered with a binder (usually on a bitumen basis), which is additional hydrophobization. As practice has shown, screenings and gravels of gabbroid rocks (for example, the Golodai-Gora deposit) and their chemical composition similar to them with significant radio absorption in the microwave range are best suited for such an operation. The ability of such materials to quickly dehydrate and bulk hydrophobize with solutions of organosilicon fluids allows to obtain a hydrophobic, and hence frost-resistant, filler of expansion joints.

Comparative tests were carried out on heating crushed stone using 2.4 GHz microwave radiation, which revealed the advantages of gabbroid rocks - gabbro-diabase compared to granites, with the same power, it takes three times more time (energy) to heat granite to temperatures above 150 ° C than for gabbro-diabase or gabbro-norita see table. 1. Thus, gabbroid rocks have shown an advantage as radar absorbing materials compared to granites. Rubble absorption was also monitored. Gabbroid rocks show lower absorption (water absorption), which is also their advantage.

Table 1

Heated samples of air-dry gravel (0.5 kg each, fractions 5-10 mm) in a microwave oven (1000 W), with an initial temperature of gravel 18 ° C. Requirements for the value of absorption according to PNST 127 - 2016 The method of volumetric design of the alkaline microgravity is not more than 2.0%. The absorption for the initial granite crushed stone fraction of 5-10 mm 1.16%, for crushed stone gabbroid rocks 0.38%.

One of the important disadvantages of expansion joints on a bitumen binder is the low wear resistance and hardness of the filler. For example, quartz sand and screenings have a Mohs hardness of no higher than 6.5, which is not enough when in contact with studded tires, granite and gabbro also do not reach the Mohs scale of 7. Microspheres from nickel plaster and screenings of nickel plank have a value of about 8 on this scale (nickel slag and kupershlak have a microhardness of 8-6 GPa), which is enough to withstand almost any steel. Of course, there is corundum and silicon carbide used as fillers for abrasives, but they are too expensive compared to foundry slags (nickel slag and kuperslag) and cannot be delivered in large volumes as well as foundry slags.

Precipitation, mixed with oil, salt, gasoline, forms aggressive flows, which, penetrating through a degraded deformation seam, destroy the road surface. When applying the proposed composition, the degradation of the joints does not occur much longer.

RPM microspheres have the ability to heal microcracks in a bituminous binder when exposed to external microwave heating, since the microspheres themselves and their surface are heated, fusing the adjacent surface of the bituminous binder, and therefore eliminate microcracks that arise during prolonged use of the binder with a filler. Other radar absorbing fillers, for example gabbro-diabase, have the same property, but the non-spherical surface does not allow them to fully display this property. Also, these beads have the property of self-healing microcracks (and cracks) when heated, for example, during the summer period of the same expansion joints. There is a method of heating (in winter) sections of railway tracks (arrows, crossings) to maintain their mobility, like it is possible, by heating the most important expansion joints in one way or another, to maintain their ductility (and mobility) without cracking in extreme weather conditions.

The presence of microspheres (spherical-shaped bodies) in the composite increases its ability to withstand bending and shock loads (see the Dissertation of Andrei Evgenievich Akimov, topic: “Improving the quality of asphalt concrete by treating bitumen with an ultrahigh frequency field”, candidate of technical sciences. Belgorod, 2010). It says: "The nature of the influence of binder processing depending on the parameters of the microwave generator on the physico-mechanical characteristics of bitumen, which consists in changing the viscosity, increasing the softening temperature, increasing cohesive strength and adhesion to mineral materials, which leads to an increase in the quality of asphalt concrete, is revealed" . This confirms the proposed method of heating expansion joints, with radar absorbing fillers, as contributing to an increase in the quality of the joint.

Comparative mechanical tests of crushed stone of gabbroid rocks - gabbro-diabase prepared (heated with 2.4 GHz microwave radiation in the presence of an organosilicon water-repellent agent with the addition of microspheres followed by the addition of bitumen-polymer mastic of the BND60 \ 90 brand to a mixture heated to 135 ° C) were carried out, which revealed the advantages as a material for expansion joints. Several dozen samples of the following grain composition were made:

1. gravel of gabbro-diabase 5-10 mm - 77% by weight, microspheres of gabbro-diabase 50-315 μm - 10% by weight, the rest is bitumen-polymer mastic PBB 40 according to GOST R 52056 (1.5% organosilicon water-repellent).

2. crushed stone of gabbro-diabase 2-10 mm - 77% by weight, microspheres from gabbro-diabase 50-315 μm - 10% by weight, the rest is bitumen-polymer mastic PBB 40 according to GOST R 52056 (1.5% organosilicon water-repellent

The tests were carried out by the depth of indentation of the dies at a temperature of 40 ° C for 30 minutes using a stamp with a support area of 500 mm ² . The tests were conducted according to GOST R 54400-2011. The samples showed the value of the indentation depth of the stamp: No. 1 - 6.5 mm, No. 2 - 17 mm). When comparing with control (traditional) samples tested by the same procedure with the following characteristics: 1. Control composition (test result (stamp): basic + repeated)

Crushed stone 10-15 - 66%, Crushed stone diabase 5-10 mm - 16.5%, Crushed stone diabase 2-5 mm - 4.5%, PBB 40 - 13%; Received: 1.09 mm (indentation depth), (PBB from above); 1.97 mm (indentation depth), (crushed stone from above) - i.e. the position in which the cubes were made, the addition of microspheres increases the indentation depth. A further increase in the% content of microspheres (20-30%) led to greater sample mobility — self-leveling, self-healing (cracks).

Samples were also tested for frost resistance in the cycle: freezing to -30 ° C followed by thawing to + 40 ° C, many times. No destruction of the samples (batches with 10% of the beads) was observed.

The higher mobility of the samples compared to traditional ones (for example No. 2) shows their high ability to self-leveling (self-healing), which means their suitability for expansion joints.

In the document “Guidelines for the restoration of asphalt concrete pavements and the foundations of roads by cold regeneration methods. - Ed. official - Branch. dor. method. document / M-transp. Russian Federation, State. service dor. households (Rosavtodor). - M., 2002. - 56 pp. ”Shows all the main advantages of microwave processing of road surfaces compared to traditional mechanical, infrared and others, for example, it states:“ Using a microwave device to repair joints, the coating is restored without removing old asphalt concrete, heating the strip along the joint with a width of up to 30 cm and a depth of up to 10 cm. In this case, a firm grip of the heated asphalt concrete pavement with the heated cement-concrete base of the road is formed. ”Moreover:“ Smokeless low-temperature microwave technology is practically not has a harmful effect on the environment. The first created devices for the continuous repair of cracks and potholes in an asphalt concrete pavement simultaneously heat the patch and the base on which it is applied for 5 minutes. In this case, a strong adhesion of the patch material to the base is formed, which eliminates the penetration of moisture under the patch, which leads in winter to its separation from the base. Moreover, there is no operation for cold gouging of asphalt concrete under a patch, which is accompanied by the formation of pieces of old asphalt concrete requiring recycling and the additional consumption of a new asphalt mixture. Traditional repair methods usually do not provide a tight connection between the patch and the base, and often the same pothole has to be repaired up to 8 times during the winter. Currently, in the USA there are microwave heating devices installed on trucks, the operation of which is based on the use of old damaged asphalt concrete to seal a pothole, i.e. achieved close to 100% its use to restore coverage. Unlike conventional repairs that are carried out on a dry surface, sealing potholes using microwave heating can be done in any weather, as water, absorbing microwave energy, evaporates and is removed from the area of the heated patch and base. ”These and other materials, given in the document are fully related to the proposed materials of the invention in terms of advantages.

Claims (6)

1. Composition for filling the expansion joints of road surfaces, consisting of a chemically inert filler, including crushed stone of various fractional composition, and bitumen-polymer mastic, characterized in that gabbro-diabase rocks are used as crushed stone, along with crushed stone, gabbro-diabase rocks are used as crushed stone microspheres and / or microspheres made of radar absorbing material made by plasma technology, wherein crushed stone, microspheres and / or microspheres are pre-dried and at the same time hydrophobized silicon organic water repellents in an amount of 0.1-5.0% by weight of the processed material using microwave radiation, while the ratio of the components in the composition is as follows, wt.%: crushed stone 40.0-90.0 bitumen-polymer mastic 5.0-40.0 microspheres and / or microspheres 0.5-50.0 2. The composition according to claim 1, characterized in that the size of the fractions of crushed stone of gabbro-diabase rocks from 2.5 to 15.0 mm 3. The composition according to claim 2, characterized in that the rocks of the Goloday Gora deposit or the Uchalinskoye deposit (Bashkortostan) are used as gabbro-diabase rocks. 4. The composition according to claim 1, characterized in that as the beads and / or microspheres of the radar absorbing materials produced by the plasma technology, use beads from gabbro-diabase, pomegranate, aegirine, nickel slag, or mixtures thereof. 5. The method of preparation of the composition according to claim 1 for filling the expansion joints of road surfaces, comprising mixing crushed stone and mastic, characterized in that before mixing the crushed stone and other fillers are dried using microwave radiation and simultaneously hydrophobized with organosilicon hydrophobizing agents, preferably water-based, in 0.1-5.0% by weight of the processed material, heating and hydrophobization are carried out using microwave radiation, and immediately after drying / hydrophobization is completed, mass is added to the already heated composition iku with continuous stirring.