Analysis of the quality control of asphalt mixing plant

Analysis of the quality control of asphalt mixing plant

Asphalt pavement quality is good or bad depends largely on the asphalt and concrete paving quality. Batch mixing plant works after you issue the boot command is the central control room, cold aggregate silos into the hot silo room. The aggregate and powder weighing scales measure, then input mix within the weigh of the hot asphalt and then sprayed into the cylinder. After mixing, into the final product, unloading hoppers, and finally through discharge gate finished material placed on the truck. Aggregate transport, drying, screening and powder and asphalt delivery is controlled, according to the cycle.

Asphalt-concrete mixing plant is mainly reflected in the indicators of quality of production quality – stability and flow values, stability and flow characterization of high temperature stability and resistance to deformation of mixture, is actually of asphalt concrete material strength and deformation of materials after the formation of the indicator. So we control the quality of mixture starting from the following aspects.

(A) the aggregate

Coarse aggregate particle size is 2.36~25mm stone is needed in concrete by aggregate particle locking provides stability and displacement by friction resistance. This requires it should meet the technical requirements of asphalt concrete mechanical properties, and have a definite shape (shape concrete compactness, high temperature stability and pavement structural strength). Requirements of coarse aggregate is broken after the rough surfaces and edges of square particles. Low content of needle and plate, aggregates also have high internal friction.

(B) fine aggregate

Fine aggregate refers to the diameter between 0.075~2.36mm rock, Tailings and ore powder clean does not contain clay and other harmful substances, squaring it should be possible to increase locking between particles and reducing aggregate porosity, increasing the stability of the mixture.

(C) bitumen

Before use check whether the asphalt of the indicators in line with technical requirements of road petroleum asphalt, including penetration, strength, softening point, flash point, melting, waxy, thin film oven heating test indicators.

Asphalt markings should be selected according to local climate conditions, selection of asphalt grade higher, greater penetration, lower consistency. Application of low temperature areas, built into the pavement's low temperature anti-cracking performance possible, but poor temperature stability. Usually selected according to different levels of different types of asphalt, more dilute asphalt surface layer should be used to improve the crack resistance of surface layer. While the lower thicker asphalt to improve resistance to rutting. The consistency of asphalt, the higher penetration index of PI, the higher pavement rutting resistance of high temperature stability and stronger, but poor temperature crack resistance. So construction can be mixed with a variety of asphalt modifier to improve high temperature stability and low temperature crack of asphalt pavement. Wax content should be below 3%, wax content is too high, high temperature stability and low temperature crack resistance of road, will also affect the adhesion of the asphalt.

(D) mix control

Target mix design should be selected in the trial, after you set the number of levels and distribution, Marshall test to determine the optimum asphalt content, proportion of ingredients to determine the specifications of the silo. After to material time has order, makes was heating of new mine material in dry tube of burning mouth end of out material mouth from within tube flow to outside tube within class in the, and while arrived of fill material, mixed material by dry stirred, from unloading material mouth discharge, mixed material for screening, and adjustment the specifications material warehouse and fill material of tie than, until key screen hole through rate and target level distribution range in the value of errors in provides value within.

(E) the temperature control

In specification in the, asphalt heating control in 150~170℃, mine material temperature than asphalt high 10~20℃, mixed material factory temperature for 140~155℃, asphalt mixed material finished material factory temperature directly effect assessment Pu quality and grind pressure quality, transport to assessment Pu machine using Shi, temperature control in 135~150℃ Zhijian, initially grind pressure temperature cannot below 135 ℃, last grind pressure temperature not below 110 ℃, open traffic not above 60 ℃, production process in the at any time detection finished material temperature, Timely feedback to the operator's cab, to control the temperature.

(Vi) oil stone ratio control

Asphalt asphalt asphalt concrete quality and adding materials such as the ratio of the mass of sand, is the most important indexes of asphalt concrete, asphalt-stone ratio is too large, spreading after rolling "pancake" asphalt-stone ratio is too small, the concrete material, and rolled deformed, are considered accidents.

(VII) mix mix

All aggregate particles wrapped in all asphalt, there is no uniform package, no gray, no lumps or severe segregation, found to be burnt carbonized foam and water mixture should be discarded, usually between mixing time for 45~90S, daily, weekly, to keep testing the technical indicators, and report to the engineer for approval.