阅读说明：本技术 一种抗老化改性沥青混凝土及其制备方法 (Anti-aging modified asphalt concrete and preparation method thereof ) 是由 车春花 于 2020-07-31 设计创作，主要内容包括：本发明公开了一种抗老化改性沥青混凝土的制备方法,其特征在于包括以下步骤：(1)调节PB的比例制备不同弹性模量的SEBS；(2)准备混凝土物料；(3)将SEBS共聚物的模量由大至小逐层与混凝土通过聚合反应的方式复合；(4)将SEBS包覆的混凝土与沥青混合料复合制备得到抗老化改性沥青混凝土。本发明的制备方法步骤简单,材料经济,制备出的抗老化改性沥青混凝土的力学性能和循环稳定性能都得到了改善,在5％应变下循环压缩1000的恢复率保持在94％以上。本发明还提供一种该方法制备的抗老化改性沥青混凝土。(The invention discloses a preparation method of anti-aging modified asphalt concrete, which is characterized by comprising the following steps: (1) adjusting the proportion of PB to prepare SEBS with different elastic moduli; (2) preparing a concrete material; (3) compounding the modulus of the SEBS copolymer with concrete layer by layer from large to small in a polymerization reaction mode; (4) and compounding the SEBS-coated concrete and the asphalt mixture to obtain the anti-aging modified asphalt concrete. The preparation method disclosed by the invention is simple in steps and economical in materials, the mechanical property and the cycling stability of the prepared anti-aging modified asphalt concrete are improved, and the recovery rate of 1000 in cyclic compression under 5% strain is kept above 94%. The invention also provides the anti-aging modified asphalt concrete prepared by the method.)

1. The preparation method of the anti-aging modified asphalt concrete is characterized by comprising the following steps:

(1) preparation of a multicomponent SEBS: dissolving styrene and butadiene in a nonpolar organic solvent to obtain a mixed solution with the total mass concentration of 20-30 wt%, adding cumene hydroperoxide to initiate polymerization reaction, and generating a random chain segment of a copolymer of Polystyrene (PS) and Polybutadiene (PB); adding styrene to carry out chain extension reaction to obtain SBS base glue solution; performing hydrogenation reaction on the obtained SBS base glue solution under the action of a catalyst to obtain SEBS; respectively preparing SEBS-1, SEBS-2, SEBS-3, SEBS-4 and SEBS-5 by controlling the addition amount of PB; when the mass portion of the PB chain segment in the SEBS is 2-8 wt%, SEBS-1 is obtained; when the mass portion of the PB chain segment in the SEBS is 22-28 wt%, SEBS-2 is obtained; when the mass portion of the PB chain segment in the SEBS is 45-55 wt%, SEBS-3 is obtained; when the mass portion of the PB chain segment in the SEBS is 72-78 wt%, SEBS-4 is obtained; when the mass portion of the PB chain segment in the SEBS is 92-98 wt%, SEBS-5 is obtained;

(2) preparing concrete materials: the waste concrete is crushed again, ground and sieved to obtain concrete fine material with the grain diameter of 0.1-2.5mm, concrete medium material with the grain diameter of 2.5-6.5mm and concrete coarse material with the grain diameter of 6.5-20 mm;

(3) preparation of a concrete-SEBS multicomponent mixture: pouring the concrete fine material, the concrete medium material and the concrete coarse material into a mixed solution containing 5-10 wt% of silane coupling agent and the rest of SEBS-1, stirring, reacting at 80-90 ℃ for 5-15min, taking out and drying to obtain a mixture 1;

pouring the mixture 1 into a mixed solution containing 15-20 wt% of butadiene and the rest of SEBS-2 by mass for polymerization reaction, taking out and drying to obtain a mixture 2;

pouring the mixture 2 into a mixed solution containing 15-20 wt% of butadiene and the rest of SEBS-3 for polymerization reaction, taking out and drying to obtain a mixture 3;

pouring the mixture 3 into a mixed solution containing 15-20 wt% of butadiene and the rest of SEBS-4 by mass for polymerization reaction, taking out and drying to obtain a mixture 4;

pouring the mixture 4 into a mixed solution containing 15-20 wt% of butadiene and the remaining mass portion of SEBS-5 for polymerization reaction, taking out and drying to obtain the concrete-SEBS multi-component mixture;

(4) preparing the anti-aging modified asphalt concrete: mixing asphalt and aromatic oil with the concrete-SEBS multi-component mixture, raising the temperature to 160-175 ℃, and stirring for 45-60 min; and then preserving the heat of the stirred asphalt concrete mixture for swelling, and finally shearing, testing and developing the mixture to obtain the anti-aging modified asphalt concrete.

2. The preparation method of the anti-aging modified asphalt concrete according to claim 1, characterized by comprising the following steps: the temperature of the polymerization reaction is 55-65 ℃, the pressure is 1.5-3 atmospheric pressures, and the time is 1-2 hours.

3. The preparation method of the anti-aging modified asphalt concrete according to claim 1, characterized by comprising the following steps: the temperature of the chain extension reaction is 85-95 ℃, the pressure is 1.5-3 atmospheric pressures, and the time is 30-50 min.

4. The preparation method of the anti-aging modified asphalt concrete according to claim 1, characterized by comprising the following steps: the temperature of the hydrogenation reaction is 70-90 ℃, the pressure is 2-4 atmospheric pressures, and the time is 2-5 h.

5. The preparation method of the anti-aging modified asphalt concrete according to claim 1, characterized by comprising the following steps: in the concrete material, the mass portion of the concrete fine material is 35-45 wt%, the mass portion of the concrete material is 30-35 wt%, and the rest is the concrete coarse material.

6. The preparation method of the anti-aging modified asphalt concrete according to claim 1, characterized by comprising the following steps: the mass ratio of the asphalt to the aromatic oil to the concrete-SEBS multi-component mixture is 1: (0.1-0.15): (0.3-0.6).

7. The preparation method of the anti-aging modified asphalt concrete according to claim 1, characterized by comprising the following steps: the silane coupling agent can be one or more of KH-550 silane coupling agent, KH-570 silane coupling agent, A-151 silane coupling agent and A-171 silane coupling agent.

8. The preparation method of the anti-aging modified asphalt concrete according to claim 1, characterized by comprising the following steps: the drying temperature is 100-120 ℃, and the drying time is 30-40 min.

9. The preparation method of the anti-aging modified asphalt concrete according to claim 1, characterized by comprising the following steps: the stirring speed is 800-3000 r/min.

10. An anti-aging modified asphalt concrete prepared by the method as claimed in any one of claims 1 to 9.

Technical Field

The invention relates to the field of asphalt mixtures, in particular to an anti-aging modified asphalt concrete and a preparation method thereof.

Background

Along with the continuous development of urban construction in China, the construction waste is gradually increased every year, but the resource utilization capability of the construction waste is low, so that not only can the resource waste be caused, but also serious pollution can be brought to the air or the environment. The waste cement concrete is the main form of urban building rubbish, and is generated by demolition of broken old buildings, urban road reconstruction projects and the like. The waste concrete has poor particle shape and grading and can only be used as a low-strength material, so that the process for preparing the mixture by using the concrete and the asphalt is formed in recent years, the utilization rate of waste is improved, and the pollution to the environment is reduced. However, in the current prior art, all the preparation processes of the asphalt concrete mixture basically mix or couple the two directly; the modulus of the concrete with the grade of C20-C80 is about 25-40GPa, the modulus of the asphalt mixture is about 0.8-1.6GPa, the difference between the two is about two orders of magnitude, and the mixture prepared by directly mixing can generate cracks and further be damaged due to modulus mismatch in the long-term use process, so that the durability and the cycling stability are poor.

Disclosure of Invention

The invention aims to provide an anti-aging modified asphalt concrete and a preparation method thereof, and aims to solve the problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: the preparation method of the anti-aging modified asphalt concrete is characterized by comprising the following steps:

(1) preparation of a multicomponent SEBS: dissolving styrene and butadiene in a nonpolar organic solvent to obtain a mixed solution with the total mass concentration of 20-30 wt%, adding cumene hydroperoxide to initiate polymerization reaction, and generating a random chain segment of a copolymer of Polystyrene (PS) and Polybutadiene (PB); adding styrene to carry out chain extension reaction to obtain SBS base glue solution; performing hydrogenation reaction on the obtained SBS base glue solution under the action of a catalyst to obtain SEBS; respectively preparing SEBS-1, SEBS-2, SEBS-3, SEBS-4 and SEBS-5 by controlling the addition amount of PB; when the mass portion of the PB chain segment in the SEBS is 2-8 wt%, SEBS-1 is obtained; when the mass portion of the PB chain segment in the SEBS is 22-28 wt%, SEBS-2 is obtained; when the mass portion of the PB chain segment in the SEBS is 45-55 wt%, SEBS-3 is obtained; when the mass portion of the PB chain segment in the SEBS is 72-78 wt%, SEBS-4 is obtained; when the mass portion of the PB chain segment in the SEBS is 92-98 wt%, SEBS-5 is obtained;

in the SEBS copolymer, a PS chain segment is a plastic segment, and a PB chain segment is an elastic segment, so that the plastic elasticity and the modulus of the SEBS copolymer are changed due to the difference of the proportion of PB. The procedure obtains five SEBS copolymers with different moduli by adjusting the weight ratio of the PB chain segment, wherein the moduli of the SEBS-1, the SEBS-2, the SEBS-3, the SEBS-4 and the SEBS-5 after curing are respectively about 5-10GPa, 4-6GPa, 3-4.5GPa, 1.5-3GPa and 0.8-1.5 GPa.

(2) Preparing concrete materials: the waste concrete is crushed again, ground and sieved to obtain concrete fine material with the grain diameter of 0.1-2.5mm, concrete medium material with the grain diameter of 2.5-6.5mm and concrete coarse material with the grain diameter of 6.5-20 mm;

(3) preparation of a concrete-SEBS multicomponent mixture: pouring the concrete fine material, the concrete medium material and the concrete coarse material into a mixed solution containing 5-10 wt% of silane coupling agent and the rest of SEBS-1, stirring, reacting at 80-90 ℃ for 5-15min, taking out and drying to obtain a mixture 1; pouring the mixture 1 into a mixed solution containing 15-20 wt% of butadiene and the rest of SEBS-2 by mass for polymerization reaction, taking out and drying to obtain a mixture 2; pouring the mixture 2 into a mixed solution containing 15-20 wt% of butadiene and the rest of SEBS-3 for polymerization reaction, taking out and drying to obtain a mixture 3; pouring the mixture 3 into a mixed solution containing 15-20 wt% of butadiene and the rest of SEBS-4 by mass for polymerization reaction, taking out and drying to obtain a mixture 4; pouring the mixture 4 into a mixed solution containing 15-20 wt% of butadiene and the remaining mass portion of SEBS-5 for polymerization reaction, taking out and drying to obtain the concrete-SEBS multi-component mixture;

(4) preparing the anti-aging modified asphalt concrete: mixing asphalt and aromatic oil with the concrete-SEBS multi-component mixture, raising the temperature to 160-175 ℃, and stirring for 45-60 min; and then preserving the heat of the stirred asphalt concrete mixture for swelling, and finally shearing, testing and developing the mixture to obtain the anti-aging modified asphalt concrete.

Because the concrete material has larger modulus, surplus strength and insufficient elasticity, the concrete material is firstly coupled with the SEBS-1 with the largest modulus, and then is gradually polymerized with the SEBS-2, the SEBS-3, the SEBS-4 and the SEBS with the gradually reduced modulus, so that a multi-component layered structure with the gradually reduced modulus from inside to outside, namely the concrete-SEBS multi-component mixture, can be obtained. The outermost layer of the concrete-SEBS multi-component mixture is SEBS-5 with the modulus of about 0.8-1.5GPa, and the modulus matching can be realized by compounding the mixture with the asphalt mixture with the modulus of about 0.8-1.6 GPa.

Preferably, the polymerization reaction temperature is 55-65 ℃, the pressure is 1.5-3 atmospheric pressures, and the time is 1-2 h.

Preferably, the temperature of the chain extension reaction is 85-95 ℃, the pressure is 1.5-3 atmospheric pressures, and the time is 30-50 min.

Preferably, the temperature of the hydrogenation reaction is 70-90 ℃, the pressure is 2-4 atmospheric pressures, and the time is 2-5 h.

Preferably, in the concrete material, the mass portion of the concrete fine material is 35-45 wt%, the mass portion of the concrete material is 30-35 wt%, and the rest is the concrete coarse material.

Concrete with three particle size ranges can be obtained by smashing, grinding and screening the waste concrete, and the different particle sizes and the mass ratio can be effectively filled when the asphalt concrete mixture is prepared.

Preferably, the mass ratio of the asphalt to the aromatic oil to the concrete-SEBS multi-component mixture is 1: (0.1-0.15): (0.3-0.6).

Preferably, the silane coupling agent can be one or more of KH-550 silane coupling agent, KH-570 silane coupling agent, A-151 silane coupling agent and A-171 silane coupling agent.

Preferably, the drying temperature is 100-120 ℃, and the drying time is 30-40 min.

Preferably, the stirring speed is 800-.

The invention also provides the anti-aging modified asphalt concrete prepared by the method.

Compared with the prior art, the invention has the beneficial effects that:

(1) for the asphalt concrete for the highway, in the prior art, the concrete with higher strength and the asphalt with better elasticity are directly compounded, when the asphalt concrete is repeatedly extruded and recovered by vehicles from and to a long time, because the modulus difference between the internal concrete and the asphalt is larger, the generated deformation is also larger, and the asphalt concrete lacking the transition layer is easy to crack and be damaged. The invention firstly couples a layer of SEBS-1 with similar modulus on the surface of the concrete material, then compounds SEBS-2, SEBS-3, SEBS-4 with gradually reduced modulus and SEBS-5 with similar modulus to the asphalt, finally compounds with the asphalt mixture to realize the matching of the modulus between the materials, and the prepared anti-aging modified asphalt concrete can generate the matching of deformation between the adjacent materials due to the matching of the modulus when stressed, so that the generated micro deformation can dissipate the stress through the excellent elasticity of the SEBS, thereby avoiding the formation of cracks and improving the durability and the stability of the asphalt mixture in recycling use.

(2) According to the invention, a polymerization reaction mode is adopted when different SEBS copolymers are compounded layer by layer, polymer chains are formed among the SEBS with different moduli, and compared with a van der Waals force directly mixed, the connection mode of a large number of covalent bonds is more stable and firmer, and is not easy to damage when deformation occurs.

(3) The concrete used in the invention is the waste concrete for buildings or roads, and the waste concrete is pounded again for reuse, thereby not only avoiding the pollution to the environment, but also improving the utilization rate of wastes.

(4) The materials such as PS, PB, waste concrete and the like used in the invention are all easily available and economic, and the preparation process is simple and time-saving.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.