Stockpile life of foam stabilised material and the implications for labour intensive construction

[摘要] Various studies have been done to show that labour-based construction can meet thehigh standards normally required in the construction of roads. The organisationalrequirements that were needed to ensure the efficient use of labour have also beendealt with in various studies. Tile need for alleviation of poverty, unemployment and thenegative social impact thereof by increasing the labour input in construction isunderstood by all concerned.A further step is however necessary before the idea of increasing the . labourcomponent in any kind of roadwork can be taken seriously. Engineers need to moveforward from the policy and organisational issues associated with labour intensiveconstruction and start to provide designers with sound and innovative engineeringsolutions to overcome the hurdles experienced on the ground.The study looks at the process of foam bitumen stabilisation of soils and gravels witha view of utilising this innovative method for labour intensive construction. The materialafter having been stabilised can be placed in a stockpile. Actual durations that thematerial can safely remain in stockpile have been determined in this study to be inexcess of six months for recycled asphalt and in excess of four months for the foamstabilised sand. Foam stabilised gravel was also studied and showed that after a yearin stockpile the material failed probably due to a weakening of the bitumen andaggregate bond. Covering the stockpiled material did not show any significantdifference to that of a similar uncovered stockpile. The position within the stockpile alsodid not have much effect on the engineering properties of the stoc piled material.The fact that the foam stabilised material can be worked on when cold and that it canbe stockpiled for several months implies that the material is labour friendly and can beused in labour intensive construction of road base course layers or wearing courselayers.

[发布机构] University of the Witwatersrand