Production and Application of SBR Modified Emulsified Asphalt

Production and Application Status of Emulsified Asphalt

In recent years, large-scale investment in transportation infrastructure, and asphalt and asphalt concrete roads have become the absolute mainstream of pavement structure, accompanied by emulsified asphalt intelligent distributors, slurry seal paving vehicles, micro-surface paving vehicles, synchronous crushed The increasingly perfect and widespread use of stone sealing vehicles, ultra-thin abrasive layer paving equipment and in-situ cold regeneration combined devices has greatly promoted the use and development of emulsified asphalt, and has a higher understanding of the environmental protection, economy and convenience of construction of emulsified asphalt. and evaluation, especially in the field of road maintenance, emulsified asphalt will increasingly play its leading role and become the mainstream of the road engineering material family.

Emulsified asphalt is divided into permeable layer, sealing layer, adhesive layer and mixing type according to its use, as well as modified emulsified asphalt for surface treatment. With the development of emulsifier technology and emulsified asphalt processing equipment in my country, there are more and more varieties and uses of emulsified asphalt. However, due to the limitation of production and application technology, most of the production and application of ordinary emulsified asphalt and SBR modified emulsified asphalt are mainly in China. The production of SBS modified emulsified asphalt is mainly based on imported equipment, and the equipment and production costs are high, which limits its development and application, and its market needs to be developed and occupied by domestic enterprises. This paper focuses on summarizing the production and application of SBR modified emulsified asphalt.

Production of SBR Modified Emulsified Asphalt

Features of modified emulsified asphalt: Modified emulsified asphalt refers to the use of asphalt as the base material and polymer as the modified material. Under certain equipment and process conditions, through the action of emulsifiers and auxiliaries, the asphalt, modifier and water are made of emulsion. Mainly include SBRSBS modified emulsified asphalt, etc. Modified emulsified asphalt mainly has the following performance advantages: high temperature stability, low temperature crack resistance, high adhesion, high peeling resistance, wider application range, greater cohesion, high early strength, long service life, etc., and good mixing performance. More advantages than ordinary emulsified asphalt.

Production Technology of SBR Modified Emulsified Asphalt

Each set of emulsification equipment should design a corresponding and reasonable emulsification process according to the production requirements, including production process, raw material formula, temperature control, measurement control, oil-water ratio control, etc., especially the measurement control of oil-water ratio must use advanced electronic flowmeter. The emulsification process of different equipment is different, but it should meet the following requirements:

(1) Temperature control: The temperature of asphalt and water is the most important parameter in the emulsification process. Generally, the temperature of the soap solution is 70-75 degrees, the temperature of the asphalt is 135-130 degrees, and the heat equilibrium temperature after the soap solution is added with asphalt is less than 100 degrees, that is, it will not vaporize. The asphalt temperature is too low and the fluidity is poor, which affects the emulsification quality. It is best to store the emulsified asphalt after cooling down through a heat exchanger, and the hot water is used for recycling, saving energy and improving production efficiency.

(2) Soap liquid preparation: The addition of water, emulsifier, modifier and hydrochloric acid must be accurately measured, the reaction must be fully stirred, and the pH value of the soap liquid can be tested to meet the requirements before production.

(3) Oil-water ratio control: The required proportional control of the flow rate of asphalt and emulsifier aqueous solution is an important condition for producing qualified emulsified asphalt. It is best to use closed-loop design for the control circuit to achieve dynamic regulation from time to time to ensure the production of high-quality modified emulsified asphalt that meets the design requirements.

The most important process of producing modified emulsion asphalt with various latex as modifiers is the selection of latex and the way of adding latex. There are many methods for blending latex. At present, there are mainly two categories: adding before emulsification and blending after emulsification. The latter has poor modification effect and poor emulsion stability. It is suitable for relatively backward production equipment. The more advanced production process should be to add the latex to the prepared soap solution, and after circulating and stirring evenly, it is proportionally metered and input into the shearing machine (colloid mill) to mix with asphalt to produce modified emulsified asphalt. Latex and asphalt are under the influence of mechanical caution. Under the action of full collision and fusion, the emulsified asphalt produced after full collision has better modification and stability effect, which is the current mainstream production process.

Conclusion: Modified emulsified asphalt belongs to a dual composite thermodynamically unstable system. In addition to having exactly the same characteristics as emulsified asphalt, due to the addition of latex, the instability factor is increased. Therefore, the storage stability of modified emulsified asphalt is better than that of emulsified asphalt. It is even worse, and it is easy to separate water and stratify. Therefore, the storage period of modified emulsified asphalt is limited. During production and use, planned production and use should be carried out, moderate mixing and circulation should be maintained, and the storage tank should be capped and closed to avoid wind blowing, rain and direct light. Keep the emulsion clean, do not bring in sundries, do not store below 5 degrees Celsius, and different varieties must not be mixed. Therefore, the modified emulsified asphalt should be used as soon as possible after production, not long-term storage.