CN107386041B - Preparation method of sand-containing fog sealing layer material with self-healing function - Google Patents

Abstract

The invention provides a preparation method of a sand-containing fog sealing layer material with a self-healing function, which solves the problems that the existing fog sealing layer material is insufficient in anti-skid performance, easy to age and crack, lack of a repeated self-healing function, poor in durability and incapable of realizing self-healing by means of cyclic change of a natural environment temperature field. Firstly, selecting machine-made sand as a fine aggregate of a sand-containing fog seal and carrying out reasonable grading design; then, selecting shape memory fibers with proper phase transition temperature to carry out stretching training on the fibers, and endowing the fibers with shape memory performance; selecting thermoplastic particles with proper phase transition temperature as an additive of the sand-containing fog sealing layer, and enabling the thermoplastic particles to be melted and filled in cracks when the temperature reaches the proper temperature; then weighing a proper amount of emulsified asphalt, shape memory fibers, thermoplastic particles, fine aggregates and water, and uniformly mixing to obtain a sand-containing fog sealing layer material; and finally, by detecting the mixing uniformity, the design of the mixing ratio of the components of the sand-containing fog seal is further optimized, so that the fog seal material has good self-healing performance and anti-sliding performance.

Description

Preparation method of sand-containing fog sealing layer material with self-healing function

Technical Field

The invention discloses a preparation method of a sand-containing fog sealing layer material with a self-healing function, and belongs to the technical field of preventive maintenance of asphalt pavements.

Background

With the rapid development of road construction in China, the workload of road maintenance is increasing day by day, and a plurality of pavements are finally developed into serious structural damage so as to have to be rebuilt because the pavements cannot be maintained in time when early diseases occur. This not only makes the driver and passenger can not get comfortable driving experience when the driving, still leads to originally only spending a small amount of costs just can resume road surface performance and turn into must spend high cost repayment. Researches show that the early diseases of the pavement mainly include functional diseases, such as asphalt film peeling on the surface of aggregates, loose aggregates on the surface layer of the pavement, micro cracks, water seepage and the like, and the diseases can achieve better treatment effect by adopting timely preventive maintenance measures, thereby bringing good pavement performance.

Fog-seal has been increasingly used for preventive maintenance of asphalt pavement as one of the most effective methods for preventive maintenance in recent years. It sprays on the road surface through special machinery, permeates inside the road surface through loose stripping department and the microcrack of road surface aggregate, carries out "blood transfusion" to the road surface to resume the adhesive force of the ageing pitch of road surface, pack out microcrack and space, prevent the road surface infiltration, prolonged road surface life, postponed the higher road surface major repair of cost and mended greatly. However, at present, the fog sealing layer only seals cracks of the pavement, and after the vehicle is opened for 2-3 years, the road surface micro cracks, loose aggregates, asphalt aging and other diseases can still occur repeatedly, and the service life of the road is prolonged to a certain extent.

In addition, the anti-skid performance of the asphalt pavement can be obviously reduced due to the fog seal, and the driving safety is influenced. In recent years, sand-containing fog sealing layers are widely applied. The sand-containing fog seal is a mixture of fog seal material and sand, and is sprayed on asphalt pavement by a special sand-containing fog seal high-pressure spraying vehicle to form a thin layer, so that the same maintenance effect as the fog seal is achieved. Compared with a fog sealing layer, the sand-containing fog sealing layer is added with fine sand with a certain component, so that the friction coefficient of a pavement layer is improved, and the skid resistance of the pavement is obviously enhanced; secondly, fine sand can quickly permeate into the tiny cracks to play a role in filling, and water infiltration is more effectively prevented; meanwhile, the existence of fine sand in the sand-containing fog seal layer further improves the wear resistance and durability of the pavement. However, the sand-containing fog sealing layer still has the problem that the traditional fog sealing layer cannot solve, and the effect of the fog sealing layer is only to fill and seal pavement cracks but cannot realize self-healing of the cracks, so that the aim of continuously preventing and treating pavement diseases is fulfilled.

In fact, the self-healing performance of the asphalt material is proved by foreign scholars in the early 60 th 19 th century, but the self-healing performance of the asphalt is too weak, the asphalt is greatly influenced by the load acting intermittence time and environmental factors, and the effect of treating pavement diseases is not achieved, so that the research for enhancing the self-healing performance of the asphalt material is increasingly urgent. In recent years, researchers at home and abroad improve the self-healing performance of the asphalt material through various technologies. These techniques can be broadly classified into 2 types, namely, active enhancement techniques and passive enhancement techniques.

The active enhancement technology improves the self-healing capacity of the asphalt material through a reasonable modification mode, and researchers try to realize the self-healing and performance enhancement of the asphalt through a reversible ionic bond combination mechanism of an ionomer, and the defect that the ionomer is difficult to be uniformly mixed with the asphalt and is completely compatible; in addition, the purpose of inhibiting the crack development is achieved by continuously accumulating the nano particles to the crack under the nano action, but the nano particles are difficult to uniformly disperse in the asphalt material in the method, so that the self-healing effect is poor; also, asphalt is modified by modified cross-linked polymers, which have too high a healing temperature to meet the actual pavement performance requirements.

The passive enhancement technology is represented by a microcapsule technology, an induced heating technology and a capillary network technology, and the microcapsule technology has the defects that the microcapsule technology has a disposable self-healing effect and cannot perform self-healing continuously, and the residual cavity after the capsule is broken is not beneficial to the stability of a pavement structure; the induction type heating technology enables the asphalt to have the electric conduction capability by doping the electric conduction medium, so that the self-healing of the pavement is realized by regularly heating, but the specific method, the heating time and the heating time of the technology are difficult to determine, and the technology can be completed by depending on specific equipment, so that certain energy waste is caused.

Therefore, the traditional fog sealing material is sprayed on the asphalt pavement, so that the anti-skid performance of the pavement is obviously reduced, and the driving safety is influenced; meanwhile, no novel self-healing method for the fog sealing layer material is provided at present, which is simple and convenient to implement, can perform self-healing repeatedly, has good durability and can be realized by depending on the cyclic change of the natural environment temperature field. Therefore, the sand-containing fog sealing layer material which is more suitable for the requirement of the skid resistance of the asphalt pavement and has the self-healing function and better durability needs to be developed so as to meet the requirement of the high-speed development trend of roads in China on the preventive maintenance technology.

Disclosure of Invention

(1) Technical problem

The invention aims to provide a preparation method of a sand-containing fog sealing layer material with a self-healing function, and solves the problems that the existing fog sealing layer material is insufficient in anti-skid property, easy to age and crack, lack of a repeated self-healing function, poor in durability and incapable of realizing self-healing depending on cyclic change of a natural environment temperature field, so that the pavement maintenance effect and the pavement service performance are improved, and the service quality is improved.

(2) Technical scheme

In view of the problems of insufficient anti-skid performance, easy aging and cracking, lack of repeated self-healing function, poor durability and incapability of realizing self-healing by depending on the cyclic change of a natural environment temperature field of the existing fog seal, the invention extends into the self-healing mechanism of the fog seal material, starts from two aspects of macro and micro, enhances the self-healing performance of the fog seal material, enhances the anti-skid performance of the fog seal material by adding fine aggregates with reasonable gradation, and provides a preparation method of the sand-containing fog seal material with the self-healing function, so that the pavement cured by the sand-containing fog seal has the self-healing function in the natural environment, and the anti-skid performance of the pavement cannot be obviously reduced. The technical scheme of the invention is as follows: firstly, selecting high-quality machine-made sand as a fine aggregate of a sand-containing fog seal and carrying out reasonable grading design; then, selecting shape memory fibers with proper phase transition temperature to perform thermomechanical circular stretching training on the shape memory fibers, and determining the optimal cycle number, so that the shape memory performance is given to the fibers, and the aim of closing the microcracks of the fog sealing layer is fulfilled; meanwhile, thermoplastic particles with proper phase transition temperature are selected as an additive of the sand-containing fog sealing layer, and the additive can be melted to seal and fill cracks when reaching proper temperature; then, respectively weighing a proper amount of emulsified asphalt, shape memory fibers, thermoplastic particles, a proper amount of fine aggregates and water, and uniformly mixing to obtain a sand-containing fog sealing layer material; and finally, the mix proportion design of all components of the sand-containing fog seal is further optimized by detecting the content difference of the solid residues at the top and the bottom of the mixed emulsion, so that the fog seal material has good self-healing performance and anti-sliding performance.

(3) Advantageous effects

With the rapid development of road construction in China, more and more asphalt pavements need to be preventively maintained, so that a wide prospect is provided for application and popularization of the fog seal. The preparation method of the sand-containing fog sealing layer material with the self-healing function can obviously enhance the self-healing performance and the anti-sliding performance of the fog sealing layer material, and better solves the problems that the current fog sealing layer material has insufficient anti-sliding performance, is easy to age and crack, lacks of repeated self-healing function, has poor durability and cannot realize self-healing depending on the cyclic change of a natural environment temperature field.

According to the patent technology provided by the invention, the sand-containing fog sealing layer material with the self-healing function can be developed, is used for preventive maintenance of asphalt pavements, treats most of early functional diseases of the asphalt pavements, obviously improves the performance of the asphalt pavements, enables drivers and passengers to obtain more comfortable driving and riding environments, embodies the people-oriented construction concept, better adapts to the rapid development of road construction in China, and has good social benefits; the micro-cracks of the sand-containing fog sealing layer are closed at a proper temperature through the shape memory effect of the shape memory fibers, and then the cracks are sealed and filled by melting the thermoplastic particles at a proper temperature, so that the cracks are healed, a foundation is laid for further research and improvement of the sand-containing fog sealing layer, and the sand-containing fog sealing layer has a high scientific value; in addition, when the asphalt pavement has early diseases, the sand-containing fog sealing layer with the self-healing function is used, so that the durability of the asphalt pavement is improved, the development and repair of the asphalt pavement when the asphalt pavement has serious diseases are avoided, the cost for maintaining the high-quality asphalt pavement is obviously reduced, the service life of the pavement is effectively prolonged, and the asphalt pavement has better economic benefit.

Detailed Description

The invention provides a preparation method of a sand-containing fog sealing layer material with a self-healing function, which comprises the following specific implementation steps:

(1) selecting high-quality mechanism sand with the maximum grain diameter of 1.18mm and a certain gradation as fine aggregate of the sand-containing fog seal layer, measuring the apparent relative density, the water content and the sand equivalent of the fine aggregate, and screening to test the passing rate of each sieve pore to carry out fine aggregate gradation design;

(2) polyurethane fibers and thermoplastic particles with phase transition temperature matched with the highest temperature field of the road surface are preferably selected, wherein the fibers are used as a fog sealing layer reinforcing material and are pre-deformed in three stages of high-temperature loading and stretching, constant load keeping and temperature reduction and room-temperature unloading, so that the polyurethane fibers are endowed with a shape memory function;

(3) respectively weighing a certain amount of modified emulsified asphalt and fine aggregate, respectively weighing a certain amount of modified emulsified asphalt and drinking water according to the oilstone ratio of 7% and the water content of 7.5%, and respectively weighing pre-deformed fibers and thermoplastic particles with corresponding mass according to the fiber content of 5% and the thermoplastic particle content of 10%;

(4) mixing the weighed pre-deformed fibers, thermoplastic particles and modified emulsified asphalt, and stirring for 2 minutes at normal temperature by using an electric stirrer at the rotating speed of 200-300 revolutions per minute to prepare uniformly mixed emulsion;

(5) adding the fine aggregate and water into the prepared emulsion, continuously stirring for 30 seconds at the rotating speed of 400-600 revolutions per minute to prepare a sand-containing fog sealing layer material which is uniformly mixed, and then pouring the sand-containing fog sealing layer material into a stability test tube to stand for 5 minutes;

(6) and (3) taking the upper part 1/3 and the lower part 1/3 of the test tube to detect the content of the solid residues, calculating the content difference of the solid residues of the two parts, and if the content difference is more than 15%, continuously optimizing the proportion of each component until the difference is controlled within 15%, thereby perfecting the preparation method of the sand-containing fog sealing layer material with the self-healing function.

Claims (1)

1. A preparation method of a sand-containing fog seal material with a self-healing function is characterized by comprising the following specific steps:

(1) selecting high-quality mechanism sand with the maximum grain diameter of 1.18mm and a certain gradation as fine aggregate of the sand-containing fog seal layer, measuring the apparent relative density, the water content and the sand equivalent of the fine aggregate, and screening to test the passing rate of each sieve pore to carry out fine aggregate gradation design;

(2) polyurethane fibers and thermoplastic particles with phase transition temperature matched with a road surface temperature field are preferably selected, wherein the fibers are used as a fog sealing layer reinforcing material and are pre-deformed in three stages of high-temperature loading and stretching, constant load keeping and temperature reduction and room-temperature unloading, so that the polyurethane fibers are endowed with a shape memory function;

(3) respectively weighing a certain amount of modified emulsified asphalt and fine aggregate, respectively weighing a certain amount of modified emulsified asphalt and drinking water according to the oilstone ratio of 7% and the water content of 7.5%, and respectively weighing pre-deformed fibers and thermoplastic particles with corresponding mass according to the fiber content of 5% and the thermoplastic particle content of 10%;

(4) mixing the weighed pre-deformed fibers, thermoplastic particles and modified emulsified asphalt, and stirring for 2 minutes at normal temperature by using an electric stirrer at the rotating speed of 200-300 revolutions per minute to prepare uniformly mixed emulsion;

(5) adding the fine aggregate and water into the prepared emulsion, continuously stirring for 30 seconds at the rotating speed of 400-600 revolutions per minute to prepare a sand-containing fog sealing layer material which is uniformly mixed, and then pouring the sand-containing fog sealing layer material into a stability test tube to stand for 5 minutes;

(6) and (3) taking the upper part 1/3 and the lower part 1/3 of the test tube to detect the content of the solid residues, calculating the content difference of the solid residues of the two parts, and if the content difference is more than 15%, continuously optimizing the proportion of each component until the difference is controlled within 15%, thereby perfecting the preparation method of the sand-containing fog sealing layer material with the self-healing function.