Development of stabilized Fly Ash composite materials for Haul Road Application

Abstract

Generation of fly ash from the thermal power stations is and will remain a major challenge for the near future. At present out of 140 MT fly ash about 50% are being gainfully used. Rest remain potential environment hazard. Filling of low lying area, underground voids are some of the potential areas of bulk uses. Sub-base of haul road is one such area. An essential attributes of such usage is the strength of fly ash at different period of time. Fly ash does not have any strength. It gains strength in presence of free lime. This investigation is an attempt in that direction. The sub-base of opencast haul road typically suffers from low bearing capacity material as the local material is used. It is envisioned that stabilised fly ash has strong potential to replace the sub-base material and provide adequate resistance to t road degradation. Lime and cement were used as additives to provide reactive lime at different proportions. Laboratory experiments were carried out to evaluate the strength gain in the fly ash. Standard proctor hammer test, unconfined compressive test, Brazilian tensile test and tri-axial test were carried out to determine respective properties. Lime and cement show to be enhancing the strength profiles of the fly ash. Curing periods also has strong influence on the fly ash strength properties. 90 % fly ash and 10% lime shows the maximum strength values at 100 days curing.