Asphalt-like cementing material based on waste materials and preparation method of asphalt-like cementing material

Abstract

The invention relates to the field of preparation of asphalt-like high polymer materials, in particular to an asphalt-like cementing material based on waste materials and a preparation method of the asphalt-like cementing material. The asphalt-like cementing material is prepared from the waste rubber, the waste plastic PET and the waste grease, the utilization amount of the waste materials is large, the utilization rate is high, and the efficient and feasible method for preparing the asphalt-like cementing material from the waste materials is provided; according to the present invention, the conventional technical performance and the road key technical performance can achieve the actual construction use standard, and compared with the traditional asphalt cement, the performance is better, especially under the road surface condition with the high or low environmental temperature.

Description

Technical Field

[0001] The present invention relates to the field of preparation of asphalt-like polymer materials, and particularly to an asphalt-like binder based on waste materials and a preparation method thereof. Background Art

[0002] The hot mix asphalt pavement technology is the most common pavement technology for asphalt pavement construction at home and abroad. However, with the progress of people's awareness of environmental protection, the problems of high energy consumption and high pollution generated in the production and construction of hot mix asphalt mixtures have become increasingly prominent. Although cold mix emulsified asphalt can meet people's green environmental protection needs of reducing energy consumption and air pollution, its performance is insufficient and cannot meet the performance standards of high-grade highways. Therefore, some scholars have proposed to use polyurethane adhesives to replace asphalt as binders or cements.

[0003] The bonding strength of polyurethane is very high, and it can be cured at room temperature to form strength without heating, which can effectively protect the environment. However, its manufacturing cost and construction difficulty are major problems that prevent it from replacing asphalt. Thus, many studies on reducing the manufacturing cost of polyurethane have emerged one after another, especially the direction of recycling waste materials to manufacture polyurethane materials has attracted a lot of attention.

[0004] Currently reported patents on using waste materials to manufacture cementitious materials include those for synthesizing individual main materials used in polyurethane synthesis from waste, and those for modifying existing cementitious materials with waste materials. For example, Chinese Patent CN116970362A discloses a preparation method of a novel waterborne polyurethane adhesive based on waste PET. By introducing the terephthalate structure in the PET structure into the polyol molecular chain, not only the orderliness and rigidity of the molecular chain are improved, but also the recycling of PET waste is realized, and a waterborne polyurethane adhesive with high bonding strength and high temperature resistance is obtained. Chinese Patent CN109320981A discloses a solid waste phosphogypsum composite modified asphalt and its preparation method. By making full use of solid waste phosphogypsum and rubber powder to modify asphalt, not only the treatment problems of solid wastes such as phosphogypsum and rubber powder are solved, environmental pollution is reduced, but also the road performance of road asphalt can be further improved, and the raw material cost of road construction is reduced, thus achieving multiple purposes of waste utilization, environmental protection and improvement of road performance. This process is simple and easy to operate, and is suitable for industrial production.

[0005] In summary, the existing inventions focus on using waste materials to prepare a certain additive or using waste materials as additives and applying them to pavement binders or cementitious materials. However, there is no relevant report on completely using waste materials as the main raw material for preparing cementitious materials, and there is also no demonstration of the feasibility of using waste materials to prepare cementitious materials to replace asphalt. Summary of the Invention

[0006] Based on the problems summarized above, the present invention provides a kind of asphalt-like binder based on waste materials and its preparation method. Its main feature is to use waste materials as the main raw materials for preparation to produce an asphalt-like binder, and its conventional properties and road performance both meet the technical standards and can be used as a substitute material for asphalt binder. The specific technical solution is as follows:

[0007] A preparation method of an asphalt-like binder based on waste materials includes the following steps:

[0008] S1: Pretreat the recycled waste rubber, waste plastic PET and waste oil;

[0009] S2: Use the waste oil pretreated in S1 to prepare dimer acid through the intermediate product synthesis path of fatty acid methyl ester;

[0010] S3: Use the waste plastic PET pretreated in S1 to prepare polyurethane binder through the synthesis path from BHET to BHETPP;

[0011] S4: Use the waste rubber particles pretreated in S1 to pre-disperse the polyurethane binder prepared in S3, and at the same time perform hydrolysis resistance and surface adhesion improvement treatment on the polyurethane binder prepared in S3;

[0012] S5: Add the waste rubber particles pretreated in S1 to the polyurethane binder after the treatment in S4 to complete the preparation of the asphalt-like binder.

[0013] The pretreatment methods of the waste rubber and waste plastic PET described in S1 include:

[0014] Wash and crush the recycled waste rubber and waste plastic PET respectively. The waste rubber is crushed into rubber particles with a particle size of 0.5 - 1.5 mm and screened through a 20 - 40 mesh sieve, and the waste plastic PET is crushed to a maximum length less than 3 cm;

[0015] The pretreatment method of the waste oil described in S1 includes:

[0016] After filtering the particulate impurities from the recycled waste oil, add 0.1 wt% of phosphoric acid and stir in a water bath at 60°C for 45 min, then add 3 wt% of distilled water and continue stirring for 30 min. After completion, wash 3 - 5 times with water, and then perform vacuum distillation. Set the vacuum degree to 0.85 - 0.95 MPa and the heating temperature to 100°C, and distill until no bubbles are generated.

[0017] The preparation of dimer acid described in S2 includes two steps: preparing fatty acid methyl ester from the waste oil pretreated in S1 and preparing dimer acid from fatty acid methyl ester;

[0018] The described method for preparing fatty acid methyl ester includes:

[0019] Add glycerol to the waste oil and fat after S1 pretreatment, with the molar ratio of alcohol to acid being 0.5, then add 0.59 wt% of magnetic catalyst for vacuum distillation. Set the reaction temperature at 220 °C and the reaction time at 2.5 h. After the reaction is completed, add 2.1 wt% of magnetic solid base catalyst, then add methanol according to the molar ratio of alcohol to oil of 10:1, heat and stir at 70 °C for 1.5 h, and then let the mixed liquid stand for stratification to separate crude glycerol and fatty acid methyl ester;

[0020] The described method for preparing dimer acid from fatty acid methyl ester includes:

[0021] Add 10 wt% of active catalyst to the prepared fatty acid methyl ester, heat at 240 °C for 6 h under a nitrogen atmosphere. The obtained mixture is subjected to molecular distillation to obtain methyl dimer acid, and then the methyl dimer acid is subjected to conventional ester hydrolysis to obtain dimer acid.

[0022] The described magnetic catalyst is Al 2 O 3 -ZrO 2 / Fe 3 O 4 ; the described magnetic solid base catalyst is K 2 CO 3 -Al 2 O 3 / Fe 3 O 4 ; the described active catalyst is activated clay.

[0023] S3 Using the waste plastic PET after S1 pretreatment to prepare polyurethane binder includes four steps: preparing BHET, preparing BHETPP, preparing polyurethane prepolymer, and chain extension to obtain polyurethane binder;

[0024] The described method for preparing BHET includes:

[0025] Add ethylene glycol and zinc acetate catalyst to the waste plastic PET pretreated in S1, react the mixture at 200 °C for 3 h, then cool to 70 °C, add deionized water for dilution and stir for 30 min, filter, and place the filtrate in a cooler below 0 °C to precipitate white crystals. After centrifugal washing and drying, terephthalic acid diethylene glycol ester (BHET) is obtained;

[0026] The described method for preparing BHETPP includes:

[0027] Mix the prepared BHET and the dimer acid prepared from S2, add the DBTDL catalyst and the solvent NMP, and heat and react at 190 °C for 10 h under a nitrogen atmosphere to obtain BHET-based polyester polyol (BHETPP);

[0028] The method for preparing the polyurethane prepolymer includes:

[0029] Add methyl ethyl ketone to the prepared BHETPP and dissolve it at 70 °C, then add hexamethylene diisocyanate (HDI) and the DBTDL catalyst, react at a constant temperature of 70 °C for 1.5 h, and then add the blocking agent methyl ethyl ketoxime (MEKO) and react for 1 h to obtain the polyurethane prepolymer;

[0030] The method for chain extension to prepare the polyurethane binder includes:

[0031] Mix the polyurethane prepolymer and the chain extender diethylenetriamine (DETA) evenly in proportion to prepare the polyurethane binder.

[0032] The mass ratio of the pretreated waste plastic PET to ethylene glycol is 1:4, and the addition amount of zinc acetate is 5 wt% of the pretreated waste plastic PET; the alcohol-acid mixing ratio of BHET and dimer acid is 3:1, and the mixing ratio of the polyurethane prepolymer and the chain extender diethylenetriamine (DETA) is 80:3.

[0033] The method for pre-dispersing the polyurethane binder prepared by S3 with the waste rubber particles pretreated by S1 includes:

[0034] Take out 5 wt% of the polyurethane binder to be modified, add the rubber particles treated by S1, and the addition ratio is 1:1. Then add the dispersant, ultrasonically treat the mixture for 15 min, stir for 30 min, and then mix the treated mixture into the untreated original polyurethane binder and stir all the polyurethane binder for 1 h;

[0035] The method for improving the hydrolysis resistance and surface adhesion of the polyurethane binder prepared by S3 includes:

[0036] Add toluenesulfonyl isocyanate and the silane coupling agent KH550 to the polyurethane binder prepared by S3, and complete the modification after uniform dispersion.

[0037] The dispersant is 0.0005 wt% of pvp, the addition amount of toluenesulfonyl isocyanate is 0.5 wt% - 2 wt%, and the addition amount of the silane coupling agent KH550 is 1 wt% - 3 wt%.

[0038] Preferably, the addition amount of toluenesulfonyl isocyanate is 1 wt%, and the addition amount of the silane coupling agent KH550 is 2 wt%.

[0039] The specific preparation method of S5 includes: adding the waste rubber particles pretreated in S1 into the polyurethane binder after the modification in S4. The volume ratio of the polyurethane binder to the pretreated waste rubber particles is 4:1. After mixing and blending evenly, the preparation of the asphalt-like binder is completed.

[0040] An asphalt-like binder based on waste materials is prepared by using any one of the above-mentioned preparation methods of asphalt-like binders based on waste materials.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The present invention uses waste materials as the main raw materials to prepare an asphalt-like binder, with a large amount and high utilization rate of waste materials, providing an efficient and feasible method for preparing an asphalt-like binder by using waste materials.

[0043] (2) The conventional technical properties and key road-using technical properties of the asphalt-like binder prepared by the present invention meet the standards for actual construction use, and compared with traditional asphalt binders, its performance is better, especially under pavement conditions with higher or lower environmental temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a flowchart for preparing an asphalt-like binder based on waste materials of the present invention.

[0045] Figure 2 It is a gradation curve graph of aggregates used for comparing the road-using performance of the present invention and asphalt binders. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] The following embodiments further explain and illustrate the technical solutions of the present invention. It is specifically pointed out that each specific embodiment is a concretization and explanation of the technical solution, and should not be regarded as a limitation on the protection scope of the present invention. Those of ordinary skill in the art still have the right to modify the technical solutions of these embodiments and perform equivalent replacements on some or all of the technical features, and these modifications or replacements do not change the essence of the corresponding technical solutions and do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the present invention.

[0047] The reagents and instruments used in the embodiments can be purchased from the market, and the detection methods adopt the conventional methods well-known in the art; based on the verification of the performance of the binder prepared by using waste materials and the need for performance comparison with existing asphalt binders, the detection is mainly carried out on the water absorption rate, tensile strength and elongation at break after immersion, contact angle, adhesion, penetration and softening point, force-measured ductility test, and road-using performance (high-temperature stability, low-temperature crack resistance, water stability) of the binder.

[0048] 1. Water Absorption Test:

[0049] Refer to the standard "Polyurethane Waterproof Coating" (GB / T 19250-2013) to make the binder water absorption test specimens, determine the mass change law of the samples in a 70°C constant temperature water bath, and calculate the water absorption rate of the samples according to the mass difference before and after water absorption. The calculation formula is as follows:

[0050]

[0051] In the formula, W ar - Water absorption rate of the specimen, %; M 1 - Mass of the specimen before water absorption, g; M 2 - Mass of the specimen after water absorption, g.

[0052] 2. Tensile Strength and Elongation at Break after Immersion Test:

[0053] Refer to the standard "Determination of Tensile Properties of Plastics" (GB / T 1040.2-2006). The specimen is a dumbbell shape with dimensions of 115×25×2 mm. After the binder specimen is cured, it is placed in a 70°C constant temperature water bath for 3 days of infiltration, and then tested with a universal tensile material testing machine. The tensile speed is set at 200 mm / min. The formulas for calculating the tensile strength and elongation at break are as follows:

[0054]

[0055] TL is the tensile strength of the specimen, MPa; F is the maximum tensile force corresponding to the specimen at break, N; b is the width of the specimen fracture surface, mm; c is the thickness of the specimen fracture surface, mm;

[0056]

[0057] E is the elongation at break of the specimen, %; L is the gauge length at break of the specimen, mm; L 0 is the original gauge length of the specimen, mm.

[0058] 3. Contact Angle Measurement:

[0059] Refer to the sessile drop method. Use a tablet press to make the test samples into round pieces, measure the specimens using ethylene glycol, distilled water, and formamide as test media, capture one picture every 1 s by combining an optical system and a CCD camera, find the reference line, and measure the contact angle of the imaged pictures in the system. Take the average value after multiple measurements.

[0060] 4. Evaluation of Binder Adhesion:

[0061] First, boil the binder sample adhered to the limestone aggregate for 10 minutes, and then put it into an ultrasonic cleaner for 10 minutes. The boiling temperature is set at 80 - 85°C, and the ultrasonic temperature is 80°C. The adhesion of the binder is quantitatively evaluated using the residual mass ratio. The formula for calculating the residual mass is as follows:

[0062]

[0063] In the formula: M R is the residual mass of the sample, g; M 1 is the mass of the binder, g; M 2 is the mass of the binder before ultrasonic cleaning, g; M 3 is the mass of the binder after ultrasonic cleaning, g.

[0064] 5. Penetration and softening point tests:

[0065] Refer to JTG E20 - 2011 "Test Procedures for Bitumen and Bituminous Mixtures in Highway Engineering" to measure the penetration and softening point of the binder sample, and compare and evaluate the hardness and high - temperature stability of the binder and bitumen.

[0066] 6. Force - measuring ductility test

[0067] Use a universal tensile testing device for testing. Prepare the binder into an "eight" - shaped test mold. Before the test, keep the sample in a water bath environment at 10°C for 2 hours. During the test, the temperature is 10°C and the stretching speed is 10 mm / min. During the test, when the tensile force value is "0", stop the test. Conduct parallel tests on the same sample 3 times, and take the average value of the test results.

[0068] 7. Determination of the road - using performance of the binder

[0069] To facilitate comparison with asphalt binders, refer to the current Marshall design method for asphalt mixtures and improve the mix design of the binder according to relevant specifications. And test and compare the three most important road - using performances: high - temperature stability, low - temperature crack resistance, and water stability.

[0070] For high - temperature stability, refer to JTG E20 - 2011 "Test Procedures for Bitumen and Bituminous Mixtures in Highway Engineering". Use the wheel - rolling method to form the binder sample and conduct a rutting test under standard conditions. Evaluate the high - temperature stability of the binder by the dynamic stability and rut depth. Conduct parallel tests on each binder 3 times and take the average value. The sample size is 300 mm (length) × 300 mm (width) × 50 mm (thickness). The standard conditions for the rutting test are: test temperature 60°C ± 1°C, wheel pressure 0.7 MPa ± 0.05 MPa, wheel - rolling speed 42 times / min. Record the rut depths at 45 minutes (t1) and 60 minutes (t2), denoted as d1 and d2 respectively. The formula for calculating the dynamic stability is as follows:

[0071]

[0072] Wherein, DS is the dynamic stability of the specimen, times / mm; d 1 is the deformation corresponding to time t 1 in mm; d 2 is the deformation corresponding to time t 2 in mm; C 1 is the testing machine type coefficient, and for the crank connecting rod drive loading wheel running back and forth mode, it is 1.0; C 2 is the specimen coefficient, and for the specimen prepared in the laboratory with a width of 300 mm, it is 1.0; N is the running back and forth rolling speed of the test wheel, 42 times / min.

[0073] For the low temperature cracking resistance, referring to the method of the bending test of asphalt mixture in JTG E20 - 2011 "Test Procedures for Bitumen and Mixtures of Highway Engineering", the rut specimen of the binder is formed by the wheel rolling method, and then it is cut into a prism - shaped small beam with dimensions of 250 mm ± 2.0 mm (length) × 30 mm ± 2.0 mm (width) × 35 mm ± 2.0 mm (height) by a cutting machine. The "stress - strain" curve of the specimen under the environment of - 10℃ ± 0.5℃ is measured by a UTM universal testing machine, the loading rate is 50 mm / min, and the span of the small beam specimen is 200 mm ± 0.5 mm. Then calculate the flexural tensile strength, maximum flexural tensile strain and flexural stiffness modulus of the specimen to evaluate the low temperature cracking resistance performance of the binder. The average value is taken from three parallel tests of the mixture for each specimen. The calculation formulas for the flexural tensile strength, maximum flexural tensile strain and flexural stiffness modulus of the low temperature bending small beam test are as follows:

[0074]

[0075] Wherein, R B is the flexural tensile strength at specimen failure, MPa; ε B is the maximum flexural tensile strain at specimen failure, με; S B is the flexural stiffness modulus at specimen failure, MPa; b is the width of the specimen at the mid - span cross - section, mm; h is the height of the specimen at the mid - span cross - section, mm; L is the span of the specimen, mm; P B is the maximum load at specimen failure, N; d is the mid - span deflection at specimen failure, mm.

[0076] For the water stability, referring to the "Test Procedures for Bitumen and Mixtures in Highway Engineering" (JTG E20 - 2011), the Marshall immersion test (T0709 - 2011) and freeze - thaw splitting strength test (T0729 - 2011) of asphalt mixtures are adopted. The Marshall compaction method is used to form the Marshall cylinder specimens of the binder. The specimen size is 101.6 mm ± 0.25 mm (diameter) × 63.5 mm ± 1.3 mm (height). Among them, for the immersion Marshall test, the specimens are divided into two groups, with 3 specimens in each group. They are placed in a constant - temperature water bath at 60 °C for 30 min and 48 h respectively, and then the splitting test is carried out using a UTM universal testing machine; for the freeze - thaw splitting test, 3 specimens are also set. After vacuum saturation treatment, they are frozen in an environment at - 18 °C for 16 h, then transferred to a constant - temperature water bath at 60 °C for 24 h, and finally placed in a constant - temperature water bath at 25 °C for not less than 2 h, and then the splitting test is carried out using a UTM universal testing machine.

[0077] Example 1

[0078] A preparation method of an asphalt - like binder based on waste materials is as follows:

[0079] S1: Pretreatment of waste materials:

[0080] S11: Wash and crush the recycled waste rubber and waste plastic PET respectively. Among them, the waste rubber is crushed into rubber particles with a particle size of 0.5 - 1.5 mm and screened through a 20 - 40 - mesh sieve, and the waste plastic PET is crushed to a maximum major axis length of less than 3 cm;

[0081] S12: After filtering the particulate impurities from the recycled waste oil (mainly catering waste oil), add 0.1 wt% of phosphoric acid and stir in a 60 °C water bath for 45 min, then add 3 wt% of distilled water and continue stirring for 30 min. After completion, wash 3 - 5 times with water, and then carry out vacuum distillation. Set the vacuum degree to 0.85 - 0.95 MPa and the heating temperature to 100 °C, and distill until no bubbles are generated.

[0082] S2: Preparation of dimer acid:

[0083] S21: Add glycerol to the waste oil pretreated in S12, with the molar ratio of alcohol to acid being 0.5, and then add 0.59 wt% of Al 2 O 3 -ZrO 2 / Fe 3 O 4 magnetic catalyst for vacuum distillation. Set the reaction temperature to 220 °C and the reaction time to 2.5 h; after the reaction is completed, add 2.1 wt% of K 2 CO 3 -Al 2 O 3 / Fe 3O 4 A magnetic solid base catalyst was added, and then methanol was added in a molar ratio of alcohol to oil of 10:1. The mixture was heated and stirred at 70 °C for 1.5 h. Then, the mixed liquid was allowed to stand and layer, and the separated crude glycerol was purified and recycled, while the separated fatty acid methyl ester was reserved for use.

[0084] S22: 10 wt% of activated clay catalyst was added to the fatty acid methyl ester, and the mixture was heated at 240 °C for 6 h under a nitrogen atmosphere. The obtained mixture was subjected to molecular distillation to obtain dimethyl dimerate, and then the dimethyl dimerate was subjected to conventional ester hydrolysis to obtain dimer acid.

[0085] S3: Preparation of polyurethane binder:

[0086] S31: Ethylene glycol and zinc acetate catalyst were added to the waste plastic PET treated in S11. The mass ratio of waste plastic PET to ethylene glycol was 1:4, and the addition amount of zinc acetate was 5 wt% of the waste plastic PET. The mixture was reacted at 200 °C for 3 h, then cooled to 70 °C, diluted with deionized water and stirred for 30 min. After filtration, the filtrate was cooled below 0 °C to precipitate white crystals, which were obtained as bis(2-hydroxyethyl) terephthalate (BHET) by centrifugation, washing and drying.

[0087] S32: BHET and the dimer acid obtained in S22 were mixed in an alcohol-acid ratio of 3:1, and DBTDL catalyst and solvent NMP were added. The mixture was heated and reacted at 190 °C for 10 h under a nitrogen atmosphere to obtain BHET-based polyester polyol (BHETPP).

[0088] S33: Methyl ethyl ketone was added to BHETPP and dissolved at 70 °C. Then, hexamethylene diisocyanate (HDI) and DBTDL catalyst were added, and the mixture was reacted at a constant temperature of 70 °C for 1.5 h. Then, the blocking agent methyl ethyl ketoxime (MEKO) was added and reacted for 1 h to obtain a polyurethane prepolymer.

[0089] S34: The polyurethane prepolymer and the chain extender diethylenetriamine (DETA) were mixed evenly in a ratio of 80:3 to prepare a polyurethane binder.

[0090] S4: Modification of polyurethane binder:

[0091] S41: 5 wt% of the polyurethane binder to be modified was taken out, rubber particles treated in S11 were added in a ratio of 1:1, and 0.0005 wt% of pvp dispersant was added. The mixture was ultrasonically treated for 15 min, then stirred for 30 min, and then the treated mixture was mixed into the untreated original polyurethane binder, and all the polyurethane binders were stirred for 1 h.

[0092] S42: adding 1 wt % of toluenesulfonyl isocyanate and 2 wt % of silane coupling agent KH550 to the polyurethane binder treated in S41, and dispersing them evenly to complete the modification.

[0093] S5: Preparation of asphalt-like binder: Add the rubber particles processed in S11 to the polyurethane binder modified in S42, with the volume ratio of the polyurethane binder to the rubber particles being 4:1. Mix well to complete the preparation of the asphalt-like binder.

[0094] The main polyurethane component of the prepared binder is a closed single-component type and can be stored for a long time. When the binder is mixed for use, it only needs to be heated to 140°C to unseal it. After heating, it is mixed with aggregate and powder and then poured for construction. It can be initially solidified after 4-6 hours and completely solidified after 24-72 hours.

[0095] Example 2

[0096] A method for preparing an asphalt-like binder based on waste materials, wherein the preparation steps are substantially the same as those of Example 1, except that step S41 is omitted in step S4.

[0097] The binders prepared in Example 1 and Example 2 were compared by contact angle measurement test (after heating and unsealing at 140°C), and the results are as follows:

[0098] Table 1 Comparison of contact angle test of binders prepared in Example 1 and Example 2

[0099]

[0100] By comparison, it can be seen that the sample plane formed by the binder prepared in Example 1 has a larger contact angle when the liquid medium is dropped on it, which proves that its surface energy is smaller, and also makes it more waterproof and the dispersion effect of rubber particles in the system is better.

[0101] Embodiment 3-6

[0102] A method for preparing an asphalt-like binder based on waste materials, wherein the preparation steps are substantially the same as those of Example 1, except that in step S42, the amounts of toluenesulfonyl isocyanate added are 0%, 0.5%, 1.5%, and 2%, respectively.

[0103] The water absorption test, tensile strength and elongation at break were compared (after heating and unsealing at 140°C), and the results are as follows:

[0104] Table 2 Comparison of the effects of different toluenesulfonyl isocyanate additions on water absorption

[0105]

[0106] Table 3 Comparison of the effects of different addition amounts of toluenesulfonyl isocyanate on tensile strength and elongation at break

[0107]

[0108] Based on the above test results, the influence of different addition amounts of toluenesulfonyl isocyanate on water absorption shows a trend of first decreasing and then increasing, while the influence on tensile strength after immersion shows a trend of first increasing and then decreasing. The minimum water absorption occurs at a mixing ratio of 1.5%, and the maximum tensile strength occurs at a mixing ratio of 0.5%. For the elongation at break, except for the case of no addition, the influence of the addition amount is negligible. Generally speaking, selecting an addition amount of 1% of toluenesulfonyl isocyanate can achieve the best effect.

[0109] Examples 7 - 9

[0110] A preparation method of asphalt-like binder based on waste materials, the preparation steps are basically the same as those in Example 1, except that the addition amounts of KH550 in step S42 are 0%, 1%, and 3% respectively.

[0111] Through the comparison of the adhesion evaluation test of the binder (after heating and unsealing at 140°C and adhering to limestone aggregates), the results are as follows:

[0112] Table 4 Comparison of the effects of different addition amounts of KH550 on the adhesion of the binder

[0113]

[0114] It can be seen from the test results that the silane coupling agent KH550 has a relatively obvious improvement on the adhesion of the binder, and the addition amount shows a trend of first increasing and then decreasing. The best addition amount is 2wt%.

[0115] The asphalt-like binder prepared by the present invention uses various waste materials as the main raw materials and can be used as a substitute for asphalt binder. The following is a horizontal comparison of the key performance evaluation tests of asphalt binder to measure the replaceability of the binder of the present invention with respect to asphalt binder. The 70# A-grade road petroleum asphalt mainly used in the current market is selected as the comparative example, and its conventional technical indicators are as follows:

[0116] Table 5 Conventional technical indicators of 70# A-grade road petroleum asphalt

[0117]

[0118] The three major conventional indicators (penetration, softening point, and ductility) of the asphalt-like binder prepared in Example 1 are compared with the above asphalt binder:

[0119] Table 6 Comparison of conventional indicators of the binder of the present invention and asphalt binder

[0120]

[0121]

[0122] From the comparison results, the asphalt-like binder prepared by the present invention can meet the performance standards of the binder for road construction in terms of conventional indicators. Compared with the commonly used 70# A-grade road petroleum asphalt binder, it is more excellent in resisting temperature changes and load pressures.

[0123] In the form of a single binder, the asphalt-like binder prepared by the present invention can be substituted compared with the traditional asphalt binder. The following further proves its performance and substitution feasibility from the road performance. For the convenience of comparison, referring to the gradation type (SMA-13) of the surface layer mixture of the asphalt pavement with 70# A-grade road petroleum asphalt binder, the test indexes of various aggregates and the mineral aggregate gradation are as follows:

[0124] Table 7 Test Indexes of Coarse Aggregates

[0125]

[0126]

[0127] Table 8 Test Indexes of Fine Aggregates

[0128]

[0129] Table 9 Test Indexes of Mineral Powder

[0130]

[0131] Table 10 Mineral Aggregate Gradation Range (The gradation curve is as shown in the appendix Figure 2 as follows)

[0132]

[0133] According to the gradation range of SMA-13 type asphalt mixture in the "Technical Specification for Construction of Highway Asphalt Pavement" JTG F40-2004, the median value of the gradation is selected as the design gradation of the comparison asphalt binder, and 6.1% is selected as the best asphalt binder dosage according to the empirical data. Referring to the above gradation range of the asphalt binder, with the limit of porosity ≤ 20%, combined with the road performance characteristics of polyurethane itself, the dosage range of the binder of the present invention can be determined to be between 5% and 8%. For the convenience of comparison, 6.1% is also selected as the dosage of the asphalt-like binder of the present invention.

[0134] The comparison results of high-temperature stability performance are as follows:

[0135] Table 11 Comparison of High-Temperature Stability of the Binder of the Present Invention and Asphalt Binder for Road Use

[0136]

[0137] Since polyurethane materials have a certain effect of resisting high temperature after self-curing, they can resist load effects without significant deformation and can effectively recover the deformation caused by load effects. Therefore, the high-temperature stability of polyurethane mixtures has great advantages compared with asphalt binders.

[0138] The results of the low-temperature crack resistance performance comparison are as follows:

[0139] Table 12 Comparison of the low-temperature crack resistance of the binder of the present invention and asphalt binder for road use

[0140]

[0141]

[0142] From the comprehensive results, the stress resistance performance of the binder of the present invention at low temperature is better than that of traditional asphalt materials.

[0143] The results of the water stability performance comparison are as follows:

[0144] Table 13 Comparison of the water stability of the binder of the present invention and asphalt binder for road use

[0145]

[0146] From the comprehensive results, the performance of the binder of the present invention in resisting water erosion is better than that of traditional asphalt materials.

[0147] From the comprehensive test and comparison test results, the performance of the asphalt-like binder prepared by the present invention meets the performance requirements of road binders. Compared with traditional asphalt binders, it is more excellent in both the conventional performance and road performance of binders. In addition, the present invention uses waste materials as the main raw materials, which greatly reduces the preparation cost and road use cost of polyurethane materials, and to a certain extent narrows the gap with traditional asphalt binders in terms of application cost, especially in the application under low-temperature environments.

Claims

1. A method for preparing an asphalt-like binder based on waste materials, characterized in that: The steps include: S1: Pre-treat the recycled waste rubber, waste plastic PET and waste grease; S2: using the waste oil pretreated in S1 to prepare dimer acid via the intermediate product synthesis pathway of fatty acid methyl ester; S3: using the waste plastic PET pretreated in S1 to prepare a polyurethane binder via a synthetic route from BHET to BHETPP; S4: using the waste rubber particles pretreated in S1 to pre-disperse the polyurethane binder prepared in S3, and at the same time, performing anti-hydrolysis and surface adhesion improvement treatments on the polyurethane binder prepared in S3; S5: Add the waste rubber particles pre-treated in S1 to the polyurethane binder treated in S4 to complete the preparation of asphalt-like binder.

2. The method for preparing asphalt-like binder based on waste materials according to claim 1, characterized in that: The method for pretreating waste rubber and waste plastic PET described in S1 comprises: The recycled waste rubber and waste plastic PET are washed and crushed respectively, wherein the waste rubber is crushed into rubber particles with a particle size of 0.5-1.5 mm, and screened through a 20-40 mesh sieve, and the waste plastic PET is crushed to a maximum diameter of less than 3 cm; The waste oil pretreatment method described in S1 comprises: After filtering out particulate impurities from the recovered waste grease, add 0.1wt% phosphoric acid and stir in a 60℃ water bath for 45min, then add 3wt% distilled water and continue stirring for 30min. After completion, wash with water 3 to 5 times, and then perform reduced pressure distillation with the vacuum degree set at 0.85 to 0.95MPa and the heating temperature at 100℃, and distill until no bubbles are generated.

3. The method for preparing asphalt-like binder based on waste materials according to claim 1, characterized in that: The preparation of dimer acid in S2 includes two steps of preparing fatty acid methyl ester from waste oil pretreated in S1 and preparing dimer acid from fatty acid methyl ester; The method for preparing fatty acid methyl ester from waste oils and fats pretreated in S1 comprises: Add glycerol to the waste oil pretreated by S1, with an alcohol-acid molar ratio of 0.5, and then add 0.59wt% of a magnetic catalyst for vacuum distillation, with the reaction temperature set at 220°C and the reaction time set at 2.5h; after the reaction is completed, add 2.1wt% of a magnetic solid base catalyst, and then add methanol at a molar ratio of 10:1 for alcohol to oil, heat and stir at 70°C for 1.5h, and then let the mixed liquid stand for stratification to separate crude glycerol and fatty acid methyl ester; The method for preparing dimer acid from fatty acid methyl ester comprises: 10 wt % of active catalyst was added to the prepared fatty acid methyl ester, and the mixture was heated at 240° C. for 6 h under a nitrogen atmosphere. The obtained mixture was subjected to molecular distillation to obtain dimer acid methyl ester, and then the dimer acid methyl ester was subjected to conventional ester hydrolysis to obtain dimer acid.

4. The method for preparing asphalt-like binder based on waste materials as claimed in claim 3, characterized in that: The magnetic catalyst is Al2O3-ZrO2 / Fe3O4, the magnetic solid base catalyst is K2CO3-Al2O3 / Fe3O4, and the active catalyst is activated clay.

5. The method for preparing asphalt-like binder based on waste materials according to claim 1, characterized in that: The preparation of polyurethane binder by using the waste plastic PET pretreated in S1 through the synthesis path of BHET to BHETPP in S3 includes four steps of preparing BHET, preparing BHETPP, preparing polyurethane prepolymer and chain extension to obtain polyurethane binder; The method for preparing BHET comprises: Ethylene glycol and zinc acetate catalyst were added to the waste plastic PET pretreated by S1, and the mixture was reacted at 200°C for 3h, then cooled to 70°C, diluted with deionized water and stirred for 30min, filtered and the filtrate was cooled below 0°C to precipitate white crystals, which were washed and dried by centrifugation to obtain BHET; The method for preparing BHETPP comprises: The prepared BHET and the dimer acid prepared by S2 were mixed, and DBTDL catalyst and solvent NMP were added, and heated at 190° C. for 10 h under nitrogen atmosphere to obtain BHETPP; The method for preparing a polyurethane prepolymer comprises: Add butanone to the prepared BHETPP and dissolve it at 70°C, then add hexamethylene diisocyanate and DBTDL catalyst, react at 70°C for 1.5 hours, then add blocking agent methyl ethyl ketone oxime to react for 1 hour to obtain a polyurethane prepolymer; The method for preparing the polyurethane binder by chain extension comprises: The polyurethane prepolymer and the chain extender diethylenetriamine are mixed evenly in proportion to prepare a polyurethane binder.

6. The method for preparing asphalt-like binder based on waste materials as claimed in claim 5, characterized in that: The mass ratio of the waste plastic PET and ethylene glycol added to the pretreated waste plastic PET is 1:4, and the amount of the zinc acetate catalyst added is 5wt% of the pretreated waste plastic PET; the alkyd acid mixing ratio of BHET and dimer acid in the mixture of the prepared BHET and the dimer acid prepared by S2 is 3:1, and the mixing ratio of the polyurethane prepolymer and the chain extender diethylenetriamine is 80:

3.

7. The method for preparing asphalt-like binder based on waste materials according to claim 1, characterized in that: The method of using the waste rubber particles pre-treated in S1 to pre-disperse the polyurethane binder prepared in S3 comprises: Take out 5wt% of the modified polyurethane binder, add the rubber particles treated with S1, add in a ratio of 1:1, then add a dispersant, ultrasonically treat the mixture for 15 minutes, stir for 30 minutes, then mix the treated mixture into the untreated original polyurethane binder, and stir all the polyurethane binders for 1 hour; The method for treating the polyurethane binder prepared in S3 for anti-hydrolysis and surface adhesion improvement comprises: Toluenesulfonyl isocyanate and silane coupling agent KH550 were added to the polyurethane binder prepared in S3, and the modification was completed after being evenly dispersed.

8. The method for preparing asphalt-like binder based on waste materials according to claim 7, characterized in that: The dispersant is 0.0005wt% of pvp, the added amount of toluenesulfonyl isocyanate is 0.5wt% to 2wt%, and the added amount of the silane coupling agent KH550 is 1wt% to 3wt%.

9. The method for preparing asphalt-like binder based on waste materials according to claim 1, characterized in that: The polyurethane binder treated in S4 is added to the waste rubber particles pretreated in S1, and the volume ratio of the polyurethane binder to the pretreated waste rubber particles is 4:

1.

10. An asphalt-like binder based on waste materials, characterized in that: The preparation method is described in any one of claims 1 to 9.

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