The Use of Sasol Ash as a Road Construction Material

摘要

The CSIR's Division of Transport Technology was commissioned by Sasol Chemical Industries to undertake a study on the use of ash from the coal gasification process at their Sasolburg plant in South Africa. The plant produces large quantities of coarse and fly ash that are currently disposed of on dumps and in slimes dams. If this ash could be used as an aggregate in roads, the demand on natural reserves for aggregates could be reduced and an effective method of using the ash could be developed.rnThe study is being conducted in several phases. During the first phase, a viability study, marketing, transport and construction studies were performed and preliminary laboratory testing carried out on the ash. It was found that Sasol ash could be used as a cost-effective alternative to conventional road construction materials within 300 km from Sasolburg.rnDuring the second phase, detailed laboratory testing on the ash was undertaken. The use of unstabilized, lime stabilized and bitumen emulsion stabilized blends of coarse and fly ash was investigated for use in road pavement layers. The use of the ash as an aggregate in asphalt, slurry seals and concrete was also investigated.rnSasol have constructed a pilot ash blending plant which enables different sized portions of the ash to be blended to approximate a specified grading. Material from this pilot plant was used in the construction of trial sections using unstabilized and bitumen emulsion stabilized ash. Construction of the trial sections was performed using labour-based construction techniques. The trial sections are currently being subjected to accelerated pavement testing (APT) under the Heavy Vehicle Simulator (HVS), developed by the CSIR. Although final results of the APT are not yet available, indications are that the ash is performing well.