Warm mix asphalt is a kind of compound macromolecular wax. It is white and granular, insoluble in water. At normal temperature, it appears as solid saturated hydrocarbons of long chain. It has no pungent smell, harmless to people. With gradual acquaintance of superior performance of these analogous products in domestic market, nowadays it is popularized and applied in various construction of road-relevant project to some extent, especially suitable for the work of particular construction site (e.g. paving) in winter and night.

 

Technical characteristics:
Appearance: little white granule
Density: 1-1.5g/cm3     （25℃）
Fusion point: 115℃
Solubility: insoluble     （20℃）
Flash point:  285℃
Average molecular weight: ＞1000g/mol
PH value of aqueous solution: neutral

 

Mechanism of action:

When low melting warm mix agent is added into the asphalt mixture, the granule of warm mix agent will melt in lower temperature, then produce a mass of liquid  melted in the asphalt, thus changing the viscosity curve of the asphalt, and decreasing the temperature for mixing and stirring. Meanwhile, in road- surface temperature, it forms an elaborate crystal structure, creating a bifurcate and partly alternated curing elastic structure. Therefore, it possesses favorable pavement performance as well.

 

Main functions:
(1)Decrease the temperature for stirring asphalt to the range of 30-50℃, and extend the time of construction.
When asphalt mixture is blended with warm mix agent, the temperature for stirring (120 ℃) is decreased at least by 30℃, compared with that of hot stirring  (150℃ above), thus it can be applied to construction work in special conditions as in winter and night.

(2)Reduce environment pollution caused by emitting toxic gases, and improve the working condition for constructors.
As the blending temperature is decreased, the evaporation and emission of toxic gases will cut down immensely. For example, the emission of CO2 is decreased by 46%, the exhaust of CO is reduced by 2/3, the drainage of SO2 is decreased by 40%, the discharge of Oxidation of nitrogen gas is reduced almost by 60%, and the emission of “asphalt smoke”, which is produced in paving, can be reduced by 80% at least. Therefore, it protects the environment and the health of constructors and technicians to a great extent.

(3)Great pavement performance of anti-rutting and resisting water damage.
Warm mix agent can enhance high-temperature behavior of asphalt evidently, reduce temperature sensitivity, maintain low temperature performance of asphalt, raise softening point, degrade temperature affection performance, and upgrade penetration index. At road- surface temperature, it forms a elaborate structure, creating a bifurcate and partly alternated curing elastic structure, which can likely strengthen the ability of anti-rutting and resisting water damage of the road surface, therefore not only lowering pavement noise, but also maintaining the traffic in solidifying period of the road surface.

(4)Superior compaction capacity, improving road-surface quality
Warm mix agent can easily compact mixture, which is hard to be compacted, thus reducing rolling recycles,while hardly affecting modulus of resilience of the road surface.

(5)Reduce consumption energy, save the cost of machinery operation and subsequent road maintenance

When the road surface is under construction, heating fuel oil can be saved by 20% to
30%.Low temperature process extends srvice life of the equipment of asphalt mixture, reduces cost for repairing; due to the low temperature of construction, it can slow the oxidative rate of asphalt binder effectively, prevent asphalt from aging and hardening, and increase life span of the road. The insurance and improvement of pavement's quality will reduce occurrence of the post maintenance and related charge.

(6)Superior performance of anti-aging, extending life span of the road
The peculiarity of acid and alkali resistance of warm mix agent avoids the erosion to road surface by chemical substance, and strengthens the road's ability of anti-aging.
(7)The operation is convenient and rapid, and the storage is stable, hardly isolated.
The warm mix agent is easily mixed and stirred, hardly isolated, without special equipment. When it is added into the asphalt, simple mechanical mixing is enough, without additional devices. As it is mixed into the mineral aggregate, it can be directly blended with the mineral aggregate. It is quite compatible with asphalt. Moreover,it can be stored stably and is hardly isolated.

(8) Solve the problem of construction caused by of long distance transport
The small range of temperature change is advantageous for long distance transport, which has a great significance to road maintenance.

  

Suggested adding amount:
1.5%~3.5% the weight of the base asphalt material

 

The method of operation and construction
(1)You can adopt wet mix method and dry mix method to add warm mix agent into the asphalt mixture. The wet mix method is that granules of warm mix agent are appended into the heated asphalt separately in proportion, and the mixing ought to be homogeneous, of which the time should not be less than 30 minutes, and heating temperature of asphalt be 140～170℃.The dry mix method is that in the process of blending the asphalt mixture, you add the granule of warm mix agent into the mixture entirely while the asphalt is appended, thus the mixing time needn’t  be extended.

 (2) The crushing part of asphalt mixture blended with asphalt warm mix agent, is divided into three phases: initial pressing, repressing, final pressing. In initial pressing, steel roller is adopted, after which the vibratory roller is used for repressing, and the cylinder type roller or roller closing vibration (or roller with low amplitude and high frequency) enforce the final pressing.

 

Applications fields:
Tunnel pavement
Construction of ultra-thin asphalt pavement

Construction of rubber asphalt pavement
Heavy traffic road or airfield runway
Gus asphalt mixture and pavement for steel bridge deck
Asphalt roads under municipal construction for dense population
Asphalt concrete of various gradations