1. Asphalt mixture mixing. Because the biggest difference between sma and ordinary dense graded asphalt concrete is that sma is discontinuous graded, and the coarse aggregate has a single particle size, a large amount, less fine aggregate and a large amount of mineral powder. Fine aggregate, including stone chips and sand, only needs about 15%, which brings great difficulties to the feeding and mixing of the mixture. Therefore, the hopper and silo should be rearranged, and the aggregate silo with particle size of 5 ~ 10 mm should be added to ensure the quantity of cold materials, while the quantity of fine aggregate is very small, and the door of cold silo is rarely opened. In the process of feeding, fine aggregate should be kept dry to ensure the smooth feeding of fine aggregate. The main belt sends the coarse ingredients into the rolling hole, and the aggregate is heated by the burner. Thermocouple detects the material temperature, and automatically adjusts the air-oil ratio of the burner to make the aggregate temperature reach 190℃ ~ 200℃. Hot materials enter the vibrating screen through the hoist, and the hot materials are screened into different hot bins according to the specification requirements of the target mixture ratio (the screen size can be changed as needed). The computer controls the sliding door of each hot bin to automatically mix and measure according to the input production ratio. Due to the single particle size of sma coarse materials and less fine materials, hot materials may often be short of coarse silos (short of materials) and fine silos often overflow, so the control room operators cannot adjust the material quantity. Then add the lignin fiber into a stirring pot to dry mix with the aggregate, and then add the stone powder and asphalt metered by computer, and finish the finished product production after mixing. The dry mixing time of sma is 4 seconds to 5 seconds, and the wet mixing time is 30 seconds to 45 seconds.
Heating temperature control of various materials: asphalt heating temperature 160℃ ~ 165℃, field manufacturing temperature 165℃ ~ 170℃, maximum processing temperature 175℃, aggregate heating temperature1. The highest mixture temperature (waste temperature) is 195℃, the paving temperature is not lower than 160℃, the initial starting temperature is not lower than 150℃, the lowest recompression temperature is not lower than 130℃, and the final rolling temperature is not lower than 130℃.
2. transportation. Due to the high viscosity of asphalt mastic of sma asphalt mixture, more oil-water mixture should be coated on the bottom of the carriage of transport vehicles. In order to prevent the mixture on the surface of transport vehicles from forming a hard shell, transport vehicles must be covered with tarpaulin during transportation, and the volume of vehicles should be appropriately increased.
3. pave the road. Asphalt must be spread slowly, evenly and continuously. In the process of paving, it is not allowed to change the speed or stop halfway at will. The paving speed should be determined according to the output of mixer, the supporting conditions of construction machinery and the thickness and width of paving layer. The paving speed is 3.5m/min.
4. Scroll. Rolling process is an important link in surface construction. The eight-character policy of rolling sma is "following closely, rolling, high frequency and low amplitude", and the combination mode and rolling steps of roller are reasonably selected.