APPLICATION OF WASTEPAPER SLUDGE ASH AS MINERAL POWDER FOR HOT ASPHALT CONCRETE MIX

In this article the potentiality is proven for application of wastepaper sludge ash (WSA) as mineral powder for traditional hot asphalt concrete mix. For the comparative testing in this article the traditional limestone mineral powder is used. The chemical (oxide) composition of the aggregates was studied, while that was determined by means of DRON - 3.0 diffractometer. It was ascertained that CaO is present in wastepaper sludge ash in sufficient quantity, while it provides for utilization of this waste material as an aggregate for asphalt concrete. The limestone mineral powder granulometric composition was determined and the wastepaper sludge ash was grinded by ball grinder till the appropriate granulometric composition was reached. There were studied the main physical and mechanical parameters of bitumen 70/100 to be used for formation of asphalt binder in combination with the studied mineral aggregate. There were formed the following series of traditional hot asphalt concrete mix: on limestone mineral powder, on wastepaper sludge ash, on both limestone mineral powder and wastepaper sludge ash in ratio 50/50, 30/70, 20/80 (% w/w). By means of grading curves of dense-graded continuous mixes there was designed the chip-grain carcass of asphalt concrete mix. The asphalt concrete mix was designed based on the following characteristics: hot fine-grained densegraded asphalt concrete with residual porosity from 2 % to 5 %, with quantity of chip-grains sized more than 5 mm – 35-45 % and the maximum grain-size up to 15 mm. There was determined that WSA can perform as material to be used as mineral powder for asphalt concrete mixes. According to the requirements of Ukrainian standard (DSTU B V.2.7-119:2011), the asphalt concrete with WSA is of standard condition, but the water-saturation index approaches the acceptably allowed value, while in comparison with asphalt concrete with LMP – it is higher by 55%. Such result is due to the difference in oxide composition of the aggregates, namely lower content of products of calcareous rock in WSA. With combined application of limestone mineral powder and WSA in ratio 50/50, 30/70, 20/80 (% w/w) the water-saturation index decreases. As to the compression tensile strength and compression tensile strength after water-saturation, these indices on WSA are lower than on LMP just by 10%. The most efficient usage of WSA, considering the studies done, can be achieved when coupled with LMP in ratio 50/50.