Quality Control of Asphalt Concrete

Asphalt concrete quality is mainly reflected in the stability and flow value of the two indicators, which reflects the asphalt concrete high temperature stability and resistance to deformation, and the quality of raw materials and production processes are closely related to the control. Therefore, to control the quality of the mixture should be from the following aspects.

1. Cold material with the initial control

Cold material with the initial ratio is based on the requirements to calculate the cold storage bin ingredients motor speed and the height of the material door to determine the amount of material delivery to meet the continuous production of mixing station needs. If the primary cold distribution is not accurate, there will be expected to be expected and flash phenomenon, affecting the mixing station productivity and quality of the mixture. Test personnel should keep abreast of yard feed situation, timely sampling and screening, analysis of relevant data. According to different raw materials to adjust the primary distribution to ensure that the stability of mixing production and continuity.

2. Weighing measurement control

After drying, the aggregate is sieved through a vibrating sieve to enter a hot silo of different particle diameters. Test personnel must be sieved after the screening of aggregate screening, in order to determine the thermal silo of different particle size ratio of the amount of material used. Must be stable in the primary cold material when the hot silo screening, in order to ensure the accuracy of screening tests. Through the screening test analysis of the production mix ratio curve should be in the target mix ratio curve within the allowable range, in line with technical standards.

3. Temperature control

For asphalt mixing batch plant, the heating temperature of asphalt is controlled at 150 ~ 170 ℃, the temperature of aggregate is 10 ~ 20 ℃ higher than that of asphalt, and the factory temperature of the mixture is 140 ~ 165 ℃. If the temperature is not enough there will be flowers, the temperature is too high asphalt will be charred. Asphalt mixture of factory temperature directly affects the quality of paving and rolling. In the production process to always detect the mixture temperature, and notify the operator, in order to adjust according to the actual situation.

4. Mix the mixture

Mixing in the uniform mixing, requiring all the mineral particles were all wrapped asphalt, there is no uneven package phenomenon, no flower material, no agglomeration or segregation phenomenon. Usually the mixing time of the asphalt mixture is dry mixing for 5 seconds and wet mixing for 45 seconds. SMA mixture requires dry mix for 5 seconds, wet mix for at least 60 seconds. Mixing time can not be arbitrarily reduced to increase productivity. Mixing blades and liner in the mixing tank should be replaced after wear to ensure the orderly flow of the mixture in the mixing tank, even mixing, improve mixing quality of the mixture.

5. Monitoring of finished materials

Quality inspection personnel for each batch of finished material should be checked, flower material, segregation, the temperature is not enough or over-temperature mixture to be discarded. Find the problem in time feedback to the operator, in order to make targeted adjustment processing. Test personnel sampling the mixture every day, according to experimental procedures for experimental analysis, and experimental data feedback to the operator, found the problem in a timely manner to resolve.