CN110304865A - Old cement concrete pavement overlay repair material and its application method - Google Patents

Abstract

The invention provides an old cement concrete pavement overlay repair material and its use method, comprising the following raw material components in parts by weight: 5 to 6 parts of emulsified asphalt, 0.4 to 0.5 parts of direct injection modifier, and 0.02 to 0.02 parts of anti-stripping agent 0.03 parts, 0.2 to 0.4 parts of fiber stabilizer, 90 to 95 parts of mineral material; the mineral material includes the following components by weight: 40 to 45 parts of gravel with the first particle size, 30 parts with crushed stone with the second particle size ～40 parts, stone chips 10～15 parts, mineral powder 8～10 parts. The mineral powder included 20% slaked lime. The gradation of the mineral materials adopts the SMA‑13 mix ratio, that is, the first particle size is 9.5-13.2 mm, the second particle size is 4.75-9.5 mm, and the particle size of the stone chips is 0-4.75 mm. mm, the particle size of the mineral powder is 0-0.6 mm. When the present invention is in use, it is only necessary to directly put the direct-input modifier into the asphalt mixture mixing pot to prepare the modified asphalt mixture. This modification method completely breaks the tradition of modified asphalt, and enables the modification technology to Easy to implement.

Description

Old cement concrete pavement overlay repair material and its application method

technical field

The invention relates to road modified asphalt technology, in particular to an old cement concrete pavement repair material and a use method.

Background technique

Nowadays, the development of the road transportation industry is more and more developed. The original paved cement pavement can no longer meet the current use, so a series of damages appear on the road surface. In order to make the driving smoother, reduce traffic accidents, and increase the service life of the road, for The "white + black" road surface was transformed, and the environmentally friendly asphalt concrete pavement technology was introduced, and a high-strength plastic direct-injection modifier was applied to the blackened structure process hot asphalt mixture.

Through the direct injection modification process, various polymer materials are made into solid particle (powder) modifiers of a certain shape and size through special technology, and packed into bags and transported to the asphalt mixing base. When mixing materials, according to the designed amount, the polymer modified particles are directly put into the mixing tank through manual or equipment, and through the conventional asphalt mixture mixing process, the modified asphalt that meets the standard modification standard is produced by mixing. Asphalt mixture, this solid polymer modifier is called asphalt mixture modifier.

Direct modification of asphalt concrete eliminates the "three highs" of preparing modified asphalt, such as high temperature during processing, high storage and use temperatures; high energy consumption is required for processing, that is, more consumption of electricity, diesel, heat transfer oil, etc.; processing High emissions in the process, that is, the asphalt discharged during the processing process is poisonous and smelly, causing serious pollution and high C02 emissions. In the production process, there is no pollution problem of modified asphalt stabilizer additives at all, reducing the aging of modified asphalt in the process of processing saves a lot of energy, clean and environmentally friendly, adopting recycling waste regeneration, no special heating, insulation asphalt transportation and storage tank construction is simple Convenient Storage Convenient for long-term storage.

Contents of the invention

Aiming at the defects in the prior art, the object of the present invention is to provide an old cement concrete pavement overlay repair material and its application method. The invention adopts direct investment modification technology, which can achieve energy saving, environmental protection, and reduction of CO2 emissions, and the repaired road surface has superior strength performance, high temperature anti-rutting performance, and water stability performance.

The old cement concrete pavement overlay repair material provided by the present invention comprises the following raw material components in parts by weight: 5-6 parts of emulsified asphalt, 0.4-0.5 parts of direct injection modifier, 0.02-0.03 part of anti-stripping agent, fiber 0.2-0.4 parts of stabilizer, 90-95 parts of mineral material;

The mineral material includes the following components in parts by weight: 40-45 parts of gravel with the first particle size, 30-40 parts of crushed stone with the second particle size, 10-15 parts of stone chips, and 8-10 parts of mineral powder.

Preferably, said mineral powder comprises 20% slaked lime.

Preferably, the gradation of the mineral materials adopts the SMA-13 mix ratio, that is, the first particle size is 9.5-13.2 mm, the second particle size is 4.75-9.5 mm, and the particle size of the stone chips is 0-4.75mm, the particle size of the mineral powder is 0-0.6mm.

Preferably, the particle diameter of the direct injection modifier is 4-6 mm.

Preferably, the crushed stones and the stone chips are aggregates; the mineral powder is a filler.

The using method of the old cement concrete pavement overlay repair material provided by the invention comprises the following steps:

Step S1: drying the aggregate in the mineral material at a temperature not lower than 185°C;

Step S2: carry out secondary screening and metering on the dried aggregates, and send them into the mixing tank, and at the same time, put in the corresponding metered direct-input modifier and fiber stabilizer from the mineral powder addition hole, and carry out dry mixing , dry mixing preset time;

Step S3: adding the mineral powder and dry mixing;

Step S4: After controlling the temperature at 150°C to 160°C, spray the emulsified asphalt with the anti-stripping agent;

Step S5: wet mixing for 40-50s;

Step S6: discharging, and controlling the discharging temperature between 165°C and 185°C.

Preferably, it is characterized in that the preset time is 5s.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention breaks the complicated modification process of traditional modified asphalt. It only needs to process and produce the direct-input modifier in the factory, and then transport it to the user's asphalt mixing plant in bags, and directly open the bag to take out the demand during application. According to the site conditions, it is directly put into the asphalt storage tank, and after simple stirring, it is pumped into the asphalt mixing plant to mix the modified asphalt mixture, or the required amount of direct injection modifier is directly put into the asphalt mixture for mixing. Modified asphalt mixture is made by pot mixing. This modification method completely breaks the tradition of modified asphalt and enables the convenient implementation of modification technology.

2. In the present invention, the direct injection modifier is directly put into the mixture mixing pot of the asphalt mixing plant, which avoids the quality loss of the modifier and the asphalt two raw materials in the asphalt modification process, and there is no post-modification storage process The problem of quality stability and attenuation, and there is no hidden danger of quality attenuation of modified asphalt during the high-temperature mixing process of the mixture, which can ensure the high quality of the road surface and the modification of the mixture.

3. The present invention is a series of products developed according to the differences in the climate of vast regions in my country and the diversity of asphalt pavement structures. Users can choose freely according to their own conditions, so they have strong flexibility and applicability; Modified with formula modifier to produce high-performance asphalt mixture, which reduces the processing cost of asphalt modification, so the overall cost is better than that of traditional modified asphalt.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

Embodiment one:

In the present embodiment, the old cement concrete pavement overlay repair material provided by the present invention includes the following raw material components in parts by weight: 5.89 parts of emulsified asphalt, 0.41 part of direct-injection modifier, 0.025 part of anti-stripping agent, and fiber stabilizer 0.3 parts, 93.675 parts of mineral materials, said mineral materials include aggregates and fillers, specifically include the following components by weight: 43 parts of crushed stones with the first particle size, 35 parts of crushed stones with the second particle size, 13 parts of stone chips parts, 9 parts of mineral powder, wherein 20% slaked lime is included in the mineral powder. Wherein, the crushed stone and the stone chips are aggregates, and the mineral powder is a filler.

The gradation of the mineral materials adopts a mix ratio of SMA ~ 13, that is, the particle size of the gravel with the first particle size is 9.5 ~ 13.2mm, the particle size of the crushed stone with the second particle size is 4.75 ~ 9.5mm, and the particle size of the stone chips is 0~4.75mm, the particle size of mineral powder is 0~0.6mm.

The emulsified asphalt adopts high-viscosity emulsified asphalt, and the specific technical indicators are: the remaining amount on the sieve: 0, the sieve is 1.18mm sieve; the particle charge is cationic (+); the demulsification speed is slow to crack; Engua viscosity E25: 21 ; Asphalt standard viscosity C25, 3: 33s; evaporation residue content: 63.3%, evaporation residue penetration (100g, 25°C, 5s) (0.1mm): 75, evaporation residue softening point: 74.0°C, evaporation residue Extensibility (5°C): 25.1cm, solubility of evaporation residue (trichlorethylene): 99.3%; 1-day storage stability: 0%; 5-day storage stability: 1%.

The specific characteristics of the direct injection modifier are as follows: the appearance is small gray solid particles, the density is 0.91-0.96kg/m ³ , the particle size is 4-6mm, and the melting point is 120°C-160°C.

The specific technical indicators of the anti-peeling agent are: active matter content 99.5%; density 0.95; pH 7-8; thermal stability 300° C.; adhesiveness grade 5.

The fiber stabilizer is wood fiber, which is not corroded by acid and alkali; non-toxic, tasteless, non-polluting and non-radioactive; has good toughness, dispersibility and chemical stability, and strong oil and water absorption capabilities.

The density indexes of the gravel are: apparent density 2.724g/cm ³ , apparent relative density 2.732, gross volume relative density 2.708, and water absorption 0.53%.

The density indicators of the stone chips are: apparent density 2.629g/cm ³ , apparent relative density 2.636, gross volume relative density 2.569, and water absorption 0.97%.

The mineral powder has an apparent density of 2.715g/cm ³ and an apparent relative density of 2.720.

The technical indicators of the old cement concrete pavement overlay repair material prepared in the present invention are: gross volume relative density 2.344, calculated theoretical maximum relative density 2.439, void ratio 3.9%, mineral material void ratio 17.1%, saturation 77.8% , stability 10.68kN, flow value 3.92mm, residual stability 86.1%, dynamic stability 5171 times/mm, freeze-thaw splitting residual strength ratio 85.9%, low temperature bending failure strain 2733με, water permeability coefficient 29ml/min, asphalt mixture The leakage loss is 0.05%, and the scattering loss of asphalt mixture is 8.5%.

When using the old cement concrete pavement overlay repair material provided by the present invention, for the project with an area of A1=500*5.3=2650m ² , by 2.45 tons/m ³ mixture proportion, 260 tons of mixture consumption raw materials, then high viscosity Amount of emulsified asphalt = 260*5.89% = 15.314 tons, amount of direct injection modifier = 260*0.4% = 1.04 tons, anti-stripping agent = 260*0.0252% = 0.06552 tons, fiber stabilizer = 260*0.3% = 0.78 Tons, aggregates and fillers = 260*92.9653% = 241.71 tons.

During construction, the construction process includes the following steps:

Step 1: Preparation of the lower bearing layer, specifically: before the construction of the asphalt surface layer, first clean the lower bearing layer, remove all kinds of debris and scattered materials, close the roads before and after the operation, reduce the pollution caused by the construction, and timely Sprinkle the tack coat in preparation for the application of the asphalt overlay.

Step 2: Mixing the mixture, specifically: using a batch asphalt mixer for mixing, and feeding in strict accordance with the mix ratio. When mixing the first tray of asphalt mixture, appropriately reduce the amount of aggregate entering the drying drum and increase the flame temperature to ensure that the heating temperature of the aggregate and asphalt is higher than the specified value of 0 to 5°C when starting up, and avoid the first tray Due to insufficient temperature, the discharge temperature of the mixture is basically controlled at 160°C. Before adding the modifier, the aggregates should be dried, and the temperature of the dried aggregates should not be lower than 185°C; Put the corresponding metered direct-injection modifier and fiber stabilizer into the holes, and carry out dry mixing. The dry mixing time is 5s, that is, the aggregate feeding time of the mixing building is 5s; add mineral powder; Anti-stripping agent emulsified asphalt, and the temperature is controlled between 150 ° C ~ 160 ° C; wet mixing 40 ~ 50s; modifier asphalt mixture discharge temperature: 165 ° C ~ 185 ° C. The mixing building is equipped with computer equipment, which can store and search the amount of various materials per plate, the total amount of mixing per plate, and the mixing temperature.

Step 3: Transport the mixture, specifically: the transport vehicle should be cleaned up before loading, and to prevent sticking, a small amount of diesel oil should be painted inside the vehicle as a release agent. In order to prevent the segregation of the mixture when charging, the materials should be loaded in the order of before and after. Before leaving the factory, the temperature of the mixture is checked car by car, and it is covered with canvas to keep warm and prevent dust. In addition, it is necessary to strengthen the organization and management of the construction site, pay attention to the continuity of each link, so as to prevent the temperature of the asphalt mixture from being excessively reduced before compaction; pay attention to the insulation of the transport vehicle.

Step 4: paving the mixture, specifically: the thickness and flatness of the mixture are controlled by non-contact balance beams. During the paving process, the vibration frequency of the rammer of the paver is controlled to be greater than 30%, so as to improve the initial compaction of the road surface as much as possible. When paving, the paver paved slowly, uniformly and continuously to improve the flatness and reduce the segregation of the mixture. The paving speed in the test section was controlled at 3m/min. When paving, the material delivery vehicle stops 10-30cm in front of the paver, and is pushed forward by the paver to start unloading slowly, so as to prevent the material delivery vehicle from hitting the paver and affecting the smoothness of the paving.

In order to prevent the segregation of the mixture, keep the screw feeding uniformly and stably during the paving process, and control the height of the mixture not less than 2/3 of the height of the feeding screw to ensure the uniformity of the paving surface. The thickness of the paved mixture is measured at any time by the insertion method according to the loose paving thickness. The loose laying coefficient is 1.25.

Step 5: Compaction and forming, specifically: configure a 30t tire roller and a 13t double steel wheel roller to combine the mixture for rolling. The rolling of the mixture is carried out closely with the paving to ensure that the rolling is compact at a higher temperature, but the premise is that no serious shifting and cracks will occur. The rolling of the road roller should be carried out at a slow and uniform speed, and the rolling route and direction should not be changed arbitrarily. The turn-back position must move forward with the paver, and must not turn back on the same cross-section, so as not to cause the mixture to move or wrap and affect the smoothness of the road surface. It is strictly forbidden for the road roller to turn, turn around, add water or stay on the unrolled road section. The rolling process is divided into three stages: initial pressing, re-pressing and final pressing. Ensure that the initial pressure is completed at a temperature not lower than 165°C, the second pressure is completed at a temperature not lower than 140°C, and the final pressure is completed at a temperature not lower than 110°C.

During the initial compaction, a 13t double-drum roller is used for static compaction at a speed of 2-3Km/h. Adjacent rolling zones overlap by 1/3 of the width of the rolling wheels, and the rolling is performed from low to high. In order to prevent the wheel from sticking, the steel wheel roller adopts the method of spraying water to the rolling wheel, but the amount of water must be controlled and it must be in the form of mist to prevent the mixture from cooling down too quickly.

The re-compacting begins immediately after the initial compaction, using a 13t double-drum roller for 3 times of static compaction, the speed is 2-3Km/h, the adjacent rolling belts overlap by 1/3 of the width of the rolling wheel, and the rolling is from low to high For rolling, keep the rolling wheel clean, and remove it in time if there is any mixture sticking to the wheel. In order to prevent the wheel from sticking, the steel wheel roller adopts the method of spraying water to the rolling wheel, but the amount of water must be controlled and it must be in the form of mist to prevent the mixture from cooling down too quickly.

The final pressure is static pressure with a 13t double drum roller, and the number of passes is subject to the absence of wheel marks on the surface. During compaction, the road roller can closely follow the paver, and adopt the compaction strategy of close follow, slow pressure, high frequency and low amplitude.

Step 5: Open traffic, after the road surface temperature cools down to below 50°C, traffic can be opened.

It has been determined that the water seepage coefficient of the old cement concrete pavement overlay repair material obtained above is 29mL/min, which has good water seepage performance. The high temperature stability index is shown in Table 1, the low temperature stability index is shown in Table 2, and the water stability index is shown in Table 3.

Table 1 Results of asphalt mixture rutting test

Table 2 Bending test results of asphalt mixture

Table 3 Results of freeze-thaw splitting test of asphalt mixture

Comparative example one:

In the present embodiment, the old cement concrete pavement overlay repair material provided by the present invention includes raw materials and mineral aggregates; the raw materials include the following components by weight: 6 parts of SBS (I～D) modified asphalt, anti-stripping agent 0.024 parts, 0.3 parts of fiber stabilizer, 93.676 parts of aggregates and fillers, and the following components by weight of mineral materials: 69.5 parts of gravel, 21 parts of stone chips, and 9.5 parts of mineral powder.

For the process of area A1=500*5.3= ^2650m2 , according to the specific gravity of 2.45 tons/ ^m3 mixture, the amount of mixture is 260 tons of mixture, then the amount of modified asphalt=260*6.0%=15.6 tons, anti-stripping agent= 260*0.024%=0.0624 tons, fiber stabilizer=260*0.3%=0.78 tons, aggregate and filler=260*93.676%=243.56 tons.

The construction process and technique are consistent with Embodiment 1.

After measurement, the water permeability coefficient of the SSB modifier asphalt mixture obtained above is 19mL/min. The high temperature stability index is shown in Table 4, the low temperature stability index is shown in Table 5, and the water stability index is shown in Table 6.

Table 4 Rutting test results of asphalt mixture

Table 5 Bending test results of asphalt mixture

Table 6 Freeze-thaw splitting test results of asphalt mixture

Contrasting Table 1 and Table 4 about high-temperature stability, the rutting dynamic stability of two kinds of asphalt mixtures has all reached the requirement of hot mix modified asphalt mixture, illustrates that old cement concrete pavement overlay repair material among the present invention has good high temperature stability. The stability of the old cement concrete pavement overlay and repair material in the present invention is greater than that of the SSB modifier asphalt mixture.

Contrasting Table 2 and Table 5 about low-temperature stability, the flexural strain of two kinds of asphalt mixtures has all reached the requirement of common hot-mix asphalt mixtures in winter severe cold area, illustrates that old cement concrete pavement overlay repair material among the present invention has good Low temperature crack resistance and the bending strain of the old cement concrete pavement overlay repair material in the present invention is greater than that of the SBS modifier asphalt mixture.

Contrasting table 3 and table 6 about water stability, the splitting strength ratio of two kinds of asphalt mixtures has all reached the requirement of common hot mix asphalt mixture, illustrates that the old cement concrete pavement overlay repair material among the present invention has good water resistance stability and the splitting strength ratio of the old cement concrete pavement overlay repair material in the present invention is smaller than that of the SBS modifier asphalt mixture.

Comparing the above data comprehensively, the old cement concrete pavement overlay repair material in the present invention has better application effect.

Embodiment two:

In the present embodiment, the old cement concrete pavement overlay repair material provided by the present invention includes the following raw material components in parts by weight: 5 parts of emulsified asphalt, 0.4 part of direct injection modifier, 0.02 part of anti-stripping agent, and fiber stabilizer 0.2 parts, 90 parts of mineral materials, said mineral materials include aggregates and fillers, specifically include the following components by weight: 40 parts of crushed stones with the first particle size, 30 parts of crushed stones with the second particle size, 10 parts of stone chips 8 parts of mineral powder, wherein 20% slaked lime is included in the mineral powder.

In this embodiment, the technical indicators of each component, the gradation of mineral materials and the construction technology are all the same as those in Embodiment 1.

Embodiment three:

In this embodiment, the old cement concrete pavement overlay repair material provided by the present invention includes the following raw material components in parts by weight: 6 parts of emulsified asphalt, 0.5 part of direct injection modifier, 0.03 part of anti-stripping agent, fiber stabilizer 0.4 parts, 95 parts of mineral materials, said mineral materials include aggregates and fillers, specifically include the following components by weight: 45 parts of crushed stones with the first particle size, 40 parts of crushed stones with the second particle size, 15 parts of stone chips parts, 10 parts of mineral powder, wherein 20% slaked lime is included in the mineral powder.

In this embodiment, the technical indicators of each component, the gradation of mineral materials and the construction technology are all the same as those in Embodiment 1.

In the above three groups of embodiments, the asphalt mixture formed by designing the raw material components and then constructing them all has good high temperature stability, good low temperature crack resistance and good water stability.

In this example, the coarse aggregate in the aggregate composition can form a skeleton structure, and at the same time, an appropriate amount of fine aggregate is added according to the size of the porosity to make it have a higher degree of compactness, thereby forming a "skeleton dense Structure", so the SMA series gradation is used. Through the performance comparison test of the asphalt mixture, the SMA-13 mineral material gradation and asphalt dosage are determined. And under the comprehensive effect of suitable construction technology, the pavement repaired by using the asphalt mixture not only has good social benefits, but also has good economic benefits.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims (7)

1. An old cement concrete pavement overlay repair material is characterized in that it comprises the following raw material components in parts by weight: 5 to 6 parts of emulsified asphalt, 0.4 to 0.5 parts of direct-injection modifier, and 0.02 to 0.03 parts of anti-stripping agent parts, 0.2-0.4 parts of fiber stabilizer, 90-95 parts of mineral materials; The mineral material includes the following components in parts by weight: 40-45 parts of gravel with the first particle size, 30-40 parts of crushed stone with the second particle size, 10-15 parts of stone chips, and 8-10 parts of mineral powder. 2. The old cement concrete pavement overlay repair material according to claim 1, characterized in that the mineral powder comprises 20% slaked lime. 3. The old cement concrete pavement overlay repair material according to claim 1, characterized in that, the gradation of the mineral aggregate adopts the SMA-13 mix ratio, that is, the first particle size is 9.5-13.2mm, and the The second particle size is 4.75-9.5 mm, the particle size of the stone chips is 0-4.75 mm, and the particle size of the mineral powder is 0-0.6 mm. 4 . The old cement concrete pavement overlay repair material according to claim 1 , characterized in that the particle size of the direct injection modifier is 4-6 mm. 5. The old cement concrete pavement overlay repair material according to claim 1, characterized in that, the gravel and the stone chips are aggregates; the mineral powder is a filler. 6. a method for using the old cement concrete pavement overlay repair material described in any one of claims 1 to 5, characterized in that, comprising the steps of: Step S1: drying the aggregate in the mineral material at a temperature not lower than 185°C; Step S2: carry out secondary screening and metering on the dried aggregates, and send them into the mixing tank, and at the same time, put in the corresponding metered direct-input modifier and fiber stabilizer from the mineral powder addition hole, and carry out dry mixing , dry mixing preset time; Step S3: adding the mineral powder and dry mixing; Step S4: After controlling the temperature at 150°C to 160°C, spray the emulsified asphalt with the anti-stripping agent; Step S5: Wet mixing for 40-50s; Step S6: discharging, and controlling the discharging temperature between 165°C and 185°C. 7. The method for using the overlay repair material on old cement concrete pavement according to claim 6, characterized in that the preset time is 5s.