CN107434918B

CN107434918B - Preparation method of shape memory polyurethane modified asphalt-based caulking material

Info

Publication number: CN107434918B
Application number: CN201710760351.6A
Authority: CN
Inventors: 许涛; 汪洋; 时爽; 沈东亚
Original assignee: Nanjing Forestry University
Current assignee: Nanjing Forestry University
Priority date: 2017-08-23
Filing date: 2017-08-23
Publication date: 2019-12-06
Anticipated expiration: 2037-08-23
Also published as: CN107434918A

Abstract

the invention discloses a preparation method of a shape memory polyurethane modified asphalt-based caulking material, belongs to the technical field of road cement pavement caulking, and solves the problems that the existing asphalt-based caulking material lacks a shape memory function, is difficult to adapt to expansion and contraction change of joint width, is aged by ultraviolet rays, and has poor elastic recovery and mechanical property. Firstly, adding a proper amount of shape memory polyurethane into an asphalt-based caulking material for modification; analyzing the influence of the polyurethane on the performance of the asphalt-based caulking material by using differential scanning calorimetry, Fourier infrared analysis and other microscopic characterization methods; and finally, performing road performance test on the shape memory polyurethane modified asphalt-based caulking material to determine the optimal doping amount of the shape memory polyurethane modifier and various additives. The shape memory polyurethane modified asphalt-based caulking material prepared by the invention can better adapt to the pavement performance and the use requirement of a cement pavement, reduce the durability problems of the caulking material such as cracking, falling, water seepage, extrusion and the like, improve the stress state of the caulking material and prolong the service life of the caulking material.

Description

Preparation method of shape memory polyurethane modified asphalt-based caulking material

Technical Field

the invention discloses a preparation method of a shape memory polyurethane modified asphalt-based caulking material, belonging to the technical field of caulking of cement pavements.

Background

As a pavement form of a high-grade pavement structure, the cement pavement has the advantages of good stability, high strength, good durability and the like, is rapidly developed in China, and is one of the most main structures in the existing pavement structures at present.

Cement pavements, while having many advantages, also have fatal disadvantages, one of which is the problem of joints. The joint I is an essential important component part in the cement pavement, and is one of the weakest and most vulnerable links in the pavement structure, so that the defects of mud pumping, slab staggering, plate breaking and the like are easily generated, the integrity and the driving comfort of the cement pavement are seriously influenced, and even the life and property safety of people is influenced. Caulks having adhesive, durability, weatherability and elasticity tend to provide sealing and waterproofing when applied to joints in cementitious pavements. Therefore, the caulking material is widely applied to cement pavements, and plays a very important role in improving the pavement performance of the cement pavements and effectively prolonging the service life of the cement pavements.

At present, the cement road surface caulking materials are rarely researched in China, the cement road surface caulking materials are often unsatisfactory in use performance, the sealing effect of the cement road surface caulking materials is lost within a short time after a road surface is opened, and the cement road surface cannot exert the due road performance. In order to ensure that the caulking material can better exert the sealing effect under the working conditions of complex environment and stress conditions, prolong the service life of the caulking material, meet the use and development requirements of cement pavements and put forward higher requirements on the service performance of the caulking material.

because the asphalt-based caulking materials have the characteristics of good waterproof performance, low cost, easy material acquisition and the like, the most widely used current cement pavement caulking materials are asphalt-based caulking materials. Asphalt materials are mixtures of complex hydrocarbons and non-metallic derivatives, which have complex structures and unstable chemical compositions and tend to age under the influence of various factors, and therefore rubber or resins are often added to the main component asphalt to improve its binding properties.

the polyurethane is an amorphous material taking polyurethane as a main component, the chemical structure of the polyurethane enables water to have the characteristics of good hydrolysis resistance and hydrophobicity, and meanwhile, the urethane group also has good bonding performance, so that the polyurethane is suitable for being used as a caulking material of a cement pavement. The polyurethane caulking material has the characteristics of relatively low price, excellent performances such as wear resistance, oil resistance, low-temperature flexibility, cohesiveness and the like, good normal-temperature fluidity, easy dissolution in organic matters, simple and convenient construction process and potential shape memory function, so the polyurethane caulking material is developed quickly. However, the polyurethane has poor ageing resistance and high cohesive strength, so that the deformation capability is insufficient, phenomena of debonding from the inner wall of the joint, cohesive cracking and the like generally exist in the actual use process, and the quality and the service life of the polyurethane are seriously influenced.

In order to solve the above problems, researchers at home and abroad have recently conducted many intensive studies based on the preparation and performance analysis of polyurethane modified asphalt-based caulks. Researchers respectively select different polyurethane mixing amounts to modify the asphalt, and research results show that when the polyurethane mixing amount exceeds 30%, the difference of the softening points of the modified asphalt is large and a serious segregation phenomenon occurs, but the addition of a proper amount of the polyurethane mixing amount is beneficial to improving the flexibility of the modified asphalt, reducing the brittleness and remarkably improving the low-temperature crack resistance of the modified asphalt. The research results also show that the penetration degree of the modified asphalt is reduced, the softening point is increased and the high-temperature stability of the asphalt is improved along with the increase of the mixing amount of the polyurethane. Therefore, the economic efficiency and the performance improvement dual benefits of the polyurethane modifier are comprehensively considered, and the optimal dosage of the polyurethane modifier is determined so as to improve the road performance of the cement road surface and prolong the service life of the cement road surface.

In order to exert the advantages of polyurethane materials, have good compatibility with asphalt and have the characteristic of shape memory function, the invention takes shape memory polyurethane as a modifier to carry out optimized modification on asphalt-based caulking materials, takes the good performances of the asphalt-based caulking materials and the polyurethane caulking materials into consideration, makes up for the deficiencies of the asphalt-based caulking materials and makes up for the respective deficiencies, and can respectively exert the advantages of the structural units of the two raw materials. Therefore, the shape memory polyurethane is used for modifying the asphalt-based caulking material for the cement pavement, and the prepared shape memory polyurethane modified asphalt-based caulking material is subjected to macroscopic and microscopic property characterization so as to meet the requirement of the pavement performance of the cement pavement caulking material, and has important practical significance for solving various problems caused by the damage of the current pavement caulking material.

Therefore, the asphalt-based caulking materials adopted by the existing cement pavements have short service life, poor durability, poor elastic recovery performance and no shape memory performance, are difficult to meet the requirement of the expansion and contraction change of the joint width of the cement pavements, and are prone to tensile cracking, falling, water seepage, extrusion and other damages at the joints. The invention relates to a preparation method of a shape memory polyurethane modified asphalt-based caulking material, which is characterized in that a proper amount of shape memory polyurethane modifier is added into the asphalt-based caulking material to modify the shape memory polyurethane modified asphalt-based caulking material, and the optimal mixing amount of the shape memory polyurethane modifier is predicted, so that the shape memory polyurethane modified asphalt-based caulking material can better meet the pavement performance requirements of cement pavements. The method has important significance for prolonging the service life of the caulking material, improving the sealing effect of the caulking material and improving the durability of the caulking material of the cement pavement.

disclosure of Invention

(1) technical problem

The invention aims to provide a preparation method of a shape memory polyurethane modified asphalt-based caulking material, which adds a proper amount of shape memory polyurethane modifier into the asphalt-based caulking material for optimized modification, solves the problems that the prior asphalt-based caulking material lacks a shape memory function, is difficult to adapt to the expansion change of the width of a joint, is aged by ultraviolet rays, has poor elastic recovery and mechanical property, and further causes the durability problems of tensile cracking, falling off, water seepage, extrusion and the like of the caulking material, improves the sealing and waterproof effect and the durability of the caulking material, and prolongs the service life of the caulking material.

(2) technical scheme

In view of the fact that the existing caulking materials are difficult to adapt to the pavement performance requirements of cement pavements under complex stress conditions and environments, the caulking materials have higher requirements on the service performance of the caulking materials and are modified. The invention provides a preparation method of a shape memory polyurethane modified asphalt-based caulking material by fully considering the requirements of durability and pavement performance of a cement pavement caulking material and starting from a micro and macro characterization method. The technical scheme of the invention is as follows: firstly, adding a shape memory polyurethane modifier into an asphalt-based caulking material, and adding additives such as a plasticizer, a cross-linking agent, a catalyst, an anti-aging agent, a dispersing agent, a filler and the like to optimally modify the shape memory polyurethane modified asphalt-based caulking material; then, analyzing the influence of the shape memory polyurethane modifier on the microscopic properties of the asphalt-based caulking material by using a differential scanning calorimeter, an infrared spectrum analyzer, a scanning electron microscope, an energy spectrum analyzer and other microscopic characterization methods; finally, according to the requirement of the current specification on the road performance of the cement concrete pavement joint material, the road performance test is carried out on the shape memory polyurethane modified asphalt-based caulking material, the real stress environment of the cement pavement caulking material is simulated, the actual effect of the road performance of the caulking material is tested, the optimal value range of the mixing amount of the polyurethane modifier under the influence of various factors is determined, and the method has very important influence on prolonging the service life of the caulking material and fundamentally preventing the cement pavement from generating diseases too early.

(3) advantageous effects

With the rapid development of urban construction scale in China, the cement pavement is widely applied to roads as an important pavement structure form. The pavement performance and the service life of the cement pavement are greatly determined by the service performance, the waterproof sealing and the use effect of the jointing material at the joint, for example, the jointing material is damaged and fails, and diseases such as purfling, slab staggering, joint breakage, void separation and the like are often generated at the joint of the cement pavement. Therefore, how to improve the service performance of the cement pavement and meet the requirement of traffic development is one of the important subjects faced by road workers in China. The invention provides a preparation method for modifying a asphalt-based caulking material of a cement pavement by using a shape memory polyurethane modifier, which analyzes the influence of the polyurethane modifier on the service performance of an asphalt-based caulking material by a microscopic and macroscopic characterization method so that the prepared shape memory polyurethane modified asphalt-based caulking material can better meet the pavement performance requirement of the cement pavement. The optimal doping amount of the polyurethane modifier under the influence of various factors is determined by carrying out target optimization on the doping amount of the shape memory polyurethane modifier. The caulking material has very important values in order to solve the destruction phenomena of cracking, extrusion, falling and the like of the caulking material for the cement pavement under the conditions of natural environment and driving load, prolong the service life of the caulking material, improve the integrity, smoothness and water tightness of the cement pavement and improve the durability and driving comfort of the cement pavement.

Detailed Description

The invention aims to provide a preparation method of a shape memory polyurethane modified asphalt-based caulking material, which comprises the following specific implementation steps:

(1) Placing the matrix asphalt into a vacuum drying oven with the temperature of 150-160 ℃ for dehydration for 1 hour, then heating the matrix asphalt to 180 ℃, adding a proper amount of shape memory polyurethane modifier into the asphalt, and continuously stirring for 20min at a low speed by using a glass rod to uniformly mix the polyurethane modifier and the matrix asphalt;

(2) adding a proper amount of plasticizer according to a proportion, continuously and slowly stirring for 5-10 minutes to form a component A, weighing the cross-linking agent, the catalyst, the anti-aging agent and the dispersing agent according to a proportion, uniformly mixing to form a component B, directly adding the component B into the continuously stirred component A, and slowly stirring for 30 minutes;

(3) shearing at a high speed for 40 minutes at a shearing rate of 3000 revolutions per minute by using an asphalt high-speed shearing machine, stirring by using a glass rod, removing bubbles, putting the asphalt in a 160 ℃ environment for development for 30 minutes, putting the modified asphalt in a vacuum drying oven for dehydration for 1 hour, standing for 24 hours at normal temperature, and curing to prepare the shape memory polyurethane modified asphalt-based caulking material;

(4) The prepared shape memory polyurethane modified asphalt-based caulking material is characterized by a differential scanning calorimeter, a Fourier infrared spectrum analyzer, a field emission scanning electron microscope and an energy spectrometer, and the influence of a polyurethane modifier on the microscopic properties of the asphalt-based caulking material is analyzed;

(5) testing the high-temperature stability, low-temperature crack resistance, aging resistance, elastic recovery and mechanical property of the prepared shape memory polyurethane modified asphalt-based caulking material, and analyzing the influence of a polyurethane modifier on the pavement performance of the asphalt-based caulking material;

(6) Taking a shape memory polyurethane modified asphalt-based caulking material sample, placing the sample on a lower parallel plate of a dynamic shear rheometer, carrying out a dynamic shear rheological test on the sample, respectively measuring phase angles of the sample at 50 ℃, 60 ℃, 70 ℃ and 80 ℃, and representing shape memory performance by phase angle variation;

(7) According to the test results of the steps (4), (5) and (6), whether the prepared shape memory polyurethane modified asphalt-based caulking material meets the road performance requirement of road cement concrete pavement joint materials (JTT 203-.

Claims

1. A preparation method of a shape memory polyurethane modified asphalt-based caulking material is characterized by comprising the following specific steps:

(5) Testing the high-temperature stability, the low-temperature crack resistance, the ageing resistance, the elastic recovery and the mechanical property of the prepared shape memory polyurethane modified asphalt-based caulking material, and analyzing the influence of a polyurethane modifier on the pavement performance of the asphalt-based caulking material;