Wet-cured polyurethane modified cold-mix asphalt and preparation method thereof
Technical Field
The invention relates to the technical field of road materials, in particular to damp-cured polyurethane modified cold-mix asphalt and a preparation method thereof.
Background
The cold-mix asphalt mixture has the advantages of energy conservation, environmental protection, storage, convenient construction and the like, but has common key engineering problems of low initial stability, poor anti-rutting performance and the like. At present, the road performance of the cold-mixed asphalt mixture can be improved to a certain extent by modifying the cold-mixed asphalt by using high polymer materials such as epoxy resin, polyurethane, SBR, SBS and the like, but the essence of low stability and long curing time is not changed, the requirement of timely vehicle traffic after paving cannot be met, and the development and large-scale engineering application of the cold-mixed asphalt mixture are limited.
Different from the storable cold-mix asphalt mixture, the patent CN106977966A proposes a cold-mix cold-spread epoxy modified asphalt material and a preparation method thereof, and the patent CN111718154A proposes a preparation method of an epoxy modified cold-patch asphalt mixture. The two methods firstly prepare the component A and the component B respectively, and when the two components are used, the two components are mixed, reacted and solidified again so as to meet the requirements of paving on the same day and opening traffic on the same day. However, the two methods are complex in process, and A, B components are mixed to generate a curing reaction, so that the curing reaction cannot be stored, the curing reaction needs to be prepared at present, and the curing reaction is mostly suitable for repairing pits and diseases of pavements and small-scale application of municipal roads.
Disclosure of Invention
The invention provides a damp-cured polyurethane modified cold-mix asphalt and a preparation method thereof, which solve the problems of low stability, long curing time or complex process and incapability of storage of the existing cold-mix asphalt.
The technical scheme for realizing the invention is as follows:
the damp-cured polyurethane modified cold-mix asphalt comprises the following raw materials in parts by weight: 60-75 parts of matrix asphalt, 10-20 parts of solvent, 5-15 parts of polyurethane prepolymer, 2-5 parts of plasticizer, 1-4 parts of drying agent, 1-3 parts of stabilizer and 0.5-1.5 parts of moisture curing agent.
The method comprises the following steps:
(1) adding the matrix asphalt into a shearing and stirring kettle, heating to 90-120 ℃ to completely melt the matrix asphalt, sequentially adding a solvent, a plasticizer, a polyurethane prepolymer and a drying agent, and shearing and mixing at the speed of 1000-2000r/min for 60-120min to obtain the polyurethane modified cold-mix asphalt.
(2) And cooling the polyurethane modified cold-mixed asphalt to 60-80 ℃, adding a stabilizer and a moisture curing agent, and shearing and mixing at the speed of 800-.
The matrix asphalt is 70# petroleum asphalt with penetration degree of 50-70mm (25 ℃), softening point of 45-55 ℃ and ductility of more than 100cm (15 ℃).
The solvent is one or a combination of more of kerosene, diesel oil, 180# solvent oil or 200# solvent oil.
The polyurethane prepolymer is an isocyanate-terminated base-line polymer synthesized by polyether diol and diisocyanate. Adding diisocyanate into a reaction kettle, heating to 70-90 ℃, keeping the diisocyanate slightly excessive, adding polyether glycol into the reaction kettle for 2-3 times, keeping the temperature at 70-90 ℃, and stirring for reaction for 60-120min to obtain the isocyanate-terminated base-line type polyurethane prepolymer.
The polyether diol is one or the combination of a plurality of polypropylene glycol, polytetrahydrofuran ether glycol, ethylene glycol-propylene glycol-ethylene glycol triblock copolymer and polyoxyethylene glycol, the hydroxyl value is 60-120mg KOH/g, and the molecular weight is 1200-2000.
The diisocyanate is one or a combination of Toluene Diisocyanate (TDI), Hexamethylene Diisocyanate (HDI), diphenylmethane diisocyanate (MDI) or dicyclohexylmethane diisocyanate (HMDI).
The plasticizer is one or a combination of several of polyethylene wax, chlorinated paraffin, sasobit resin, ethylene vinyl acetate or dioctyl phthalate.
The drying agent is one or the combination of several of calcium sulfate, magnesium sulfate, calcium chloride or quicklime.
The moist curing agent is ketimine. The ketimine is prepared by the reaction of one of methyl isopropyl ketone, acetophenone and methyl isobutyl ketone with one of low molecular polyamide, polyether amine, phenol aldehyde amine and m-phenylenediamine, and the reaction temperature is 140 ℃ and 170 ℃. The ketimine generates reverse reaction when meeting water, and regenerates amine chain extender, which can crosslink and cure linear polyurethane in humid air.
The stabilizer is one or a combination of several of sulfur powder, rubber oil, cellulose and lignin.
The moisture-curing polyurethane modified cold-mix asphalt needs vacuum sealing storage, and can also be prepared into a cold-mix asphalt mixture and then stored in a vacuum sealing manner, so that the contact with moisture air is avoided, and the moisture-curing polyurethane modified cold-mix asphalt is free from pre-curing.
The invention has the beneficial effects that:
(1) according to the invention, the isocyanate-terminated polyurethane prepolymer and the moisture curing agent are introduced into the cold-mixed asphalt, the moisture curing agent and moisture are subjected to reverse reaction after being paved to generate the amine chain extender, the polyurethane prepolymer is induced to be crosslinked and cured, the strength formation and the stability improvement of the cold-mixed asphalt pavement are accelerated, and the requirement of quick traffic is met.
(2) The cold-mix asphalt and the mixture thereof prepared by the invention can be stored in a vacuum-pumping and sealing way without being prepared at present. The product has good workability and convenient construction, is in contact reaction and solidification with moisture after being paved, accelerates the formation of the strength of the cold-mixed asphalt pavement, has the Marshall stability of 7.7-8.6KN and the residual stability of more than 90 percent.
(3) The invention obtains better curing performance on the premise of not influencing the workability of cold-mixed asphalt mixture construction, and the comprehensive pavement performance is excellent.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.
Example 1
A damp solidified polyurethane modified cold mix asphalt and a preparation method thereof, the steps are as follows:
(1) adding 1 part (by weight, the same below) of Toluene Diisocyanate (TDI) into a reaction kettle, heating to 80 ℃, adding 4 parts of polypropylene glycol with the molecular weight of 1500 into the reaction kettle twice, and stirring and reacting at the temperature of 80 ℃ for 90min to obtain an isocyanate-terminated base-line type polyurethane prepolymer;
(2) adding 70 parts of matrix asphalt into a shearing and stirring kettle, heating to 100 ℃ to completely melt the matrix asphalt, sequentially adding 15 parts of diesel oil, 3 parts of polyethylene wax, 5 parts of polyurethane prepolymer and 1 part of calcium chloride drying agent, and shearing and mixing at the speed of 1500r/min for 90min to obtain polyurethane modified cold-mix asphalt;
(3) and cooling the polyurethane modified cold-mixed asphalt to 70 ℃, adding 2 parts of sulfur powder stabilizer and 0.5 part of methyl isopropyl ketone-polyamide type ketimine curing agent, and shearing and mixing at the speed of 1200r/min for 60min to obtain the damp cured polyurethane modified cold-mixed asphalt.
Example 2
A damp solidified polyurethane modified cold mix asphalt and a preparation method thereof, the steps are as follows:
(1) adding 2 parts of diphenylmethane diisocyanate (MDI) into a reaction kettle, heating to 90 ℃, adding 8 parts of ethylene glycol-propylene glycol-ethylene glycol triblock copolymer with the molecular weight of 2000 into the reaction kettle twice, and stirring and reacting at the temperature of 90 ℃ for 60min to obtain an isocyanate-terminated base-line type polyurethane prepolymer;
(2) adding 75 parts of matrix asphalt into a shearing and stirring kettle, heating to 120 ℃ to completely melt the matrix asphalt, sequentially adding 20 parts of 200# solvent oil, 2 parts of dioctyl phthalate, 10 parts of polyurethane prepolymer and 4 parts of magnesium sulfate drying agent, and shearing and mixing at the speed of 2000r/min for 60min to prepare polyurethane modified cold-mix asphalt;
(3) and cooling the polyurethane modified cold-mixed asphalt to 80 ℃, adding 3 parts of cellulose stabilizer and 1.0 part of acetophenone-polyether amine type ketimine curing agent, and shearing and mixing at the speed of 1500r/min for 30min to obtain the damp cured polyurethane modified cold-mixed asphalt.
Example 3
A damp solidified polyurethane modified cold mix asphalt and a preparation method thereof, the steps are as follows:
(1) adding 3 parts of Hexamethylene Diisocyanate (HDI) into a reaction kettle, heating to 70 ℃, adding 12 parts of polytetrahydrofuran ether glycol with the molecular weight of 1200 into the reaction kettle for three times, and stirring and reacting for 120min at the temperature of 70 ℃ to prepare an isocyanate-terminated base-line type polyurethane prepolymer;
(2) adding 60 parts of matrix asphalt into a shearing and stirring kettle, heating to 90 ℃ to completely melt the matrix asphalt, sequentially adding 10 parts of 180# solvent oil, 5 parts of sasobit resin, 15 parts of polyurethane prepolymer and 3 parts of quicklime drying agent, and shearing and mixing at the speed of 1000r/min for 120min to prepare polyurethane modified cold-mixed asphalt;
(3) and cooling the polyurethane modified cold-mixed asphalt to 60 ℃, adding 1 part of rubber oil stabilizer and 1.5 parts of acetophenone-m-phenylenediamine ketimine curing agent, and shearing and mixing at the speed of 800r/min for 90min to prepare the damp-cured polyurethane modified cold-mixed asphalt.
Comparative example 1
Adding 60 parts of matrix asphalt into a shearing and stirring kettle, heating to 90 ℃ to completely melt the matrix asphalt, sequentially adding 10 parts of 180# solvent oil, 5 parts of sasobit resin, 15 parts of commercially available polyurethane adhesive and 3 parts of quicklime drying agent, and shearing and mixing at the speed of 1000r/min for 120 min. And cooling the system to 60 ℃, adding 1 part of rubber oil stabilizer and 1.5 parts of acetophenone-m-phenylenediamine ketimine curing agent, and shearing and mixing at the speed of 800r/min for 90min to prepare the conventional polyurethane modified cold-mix asphalt.
Comparative example 1 the same materials and process conditions were used as in example 3, except that a commercially available polyurethane glue was used instead of the synthesized isocyanate-terminated base polyurethane prepolymer.
Comparative example 2
Adding 60 parts of matrix asphalt into a shearing and stirring kettle, heating to 90 ℃ to completely melt the matrix asphalt, sequentially adding 10 parts of 180# solvent oil, 5 parts of sasobit resin, 15 parts of commercially available polyurethane adhesive and 3 parts of quicklime drying agent, and shearing and mixing at the speed of 1000r/min for 120 min. And cooling the system to 60 ℃, adding 1 part of rubber oil stabilizer, and shearing and mixing at the speed of 800r/min for 90min to obtain the conventional polyurethane modified cold-mix asphalt.
Comparative example 2 the same materials and process conditions were used as in example 3, except that a commercially available polyurethane glue was used instead of the synthetic isocyanate-terminated base-line polyurethane prepolymer and no ketimine moisture curing agent was added to the process.
The wet cured polyurethane modified cold-mix asphalt obtained in the example 1-3 and the conventional polyurethane modified cold-mix asphalt obtained in the comparative example 1-2 were mixed with aggregate according to the aggregate formula LB-16 of the cold patch asphalt mixture in the technical Specification for road asphalt pavement construction, and the asphalt-aggregate ratio was 6.0%, to obtain a cold-mix asphalt mixture.
And detecting the rotational viscosity and the bonding strength of the cold-mixed asphalt according to JTG E20-2011 test procedures for road engineering asphalt and asphalt mixtures and JGJ/T110-2017 inspection standards for bonding strength of facing bricks in construction engineering. The stability and the residual stability of the cold-mixed asphalt mixture are detected according to JT/T972-2015 Bituminous pavement pit cold-patch finished product, and the detection results are shown in Table 1.
TABLE 1 results of testing the properties of examples and comparative examples
The moisture-cured polyurethane modified cold-mix asphalt prepared in examples 1-3 had low viscosity and bonding strength when uncured, and was beneficial to mixing and paving cold-mix asphalt mixtures. After the cold-mixed asphalt is paved, the wet curing agent and moisture in the cold-mixed asphalt are subjected to reverse reaction to generate an amine chain extender, the polyurethane prepolymer is induced to be crosslinked and cured, the viscosity and the bonding strength of the cold-mixed asphalt are greatly increased, and the stability of the mixture and the stability of the residue are superior to those of a comparative example. The moisture-cured polyurethane modified cold-mixed asphalt can accelerate the formation of the strength of cold-mixed asphalt pavement and meet the requirement of quick traffic of cold-mixed asphalt roads.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.