The Effect of Quarry Dust Concrete and Underlying Sub-Soil Medium on the Structural Performance of Dwelling House Ground Floors

Abstract

This research studied the effect of quarry dust concrete and the underlying subsoil medium on structural performance of dwelling houses ground floors.The volcanic rock aggregates used were graded 20mm and 5-14mm, non-graded quarry dust and Nairobi sedimentary rock as well river sand and red soil .All were subjected to physical properties tests before use and soil further tested for unconfined compression and compaction.Concrete slabs (1:3:6)cement:sand:aggregates of one metre squared in thickness of 150 and 100mm, for the various aggregates were cast, cured for 28 days and tested over the soil compacted to maximum dry density by loading on jacks for compression and strain on their surfaces measured through strain gauges attached to a data logger.The 20mm ,5-14mm, non-graded quarry dust and Nairobi sedimentary rock dust crushed at (3.3,3.2,2.2,2.1)Kn/m2 for 150mm and( 2.9,2.8,1.2,0.8)Kn/m2 for 100mm respectively .The 150mm thick for all aggregates and only graded 100mm aggregate slabs crushed above allowable imposed design load 1.5Kn/m2 for dwelling floors.The soil(sandy silty clay) when optimally compacted can safely transmit the loads of a dwelling house floor for graded aggregates from 100mm thick but for non graded the thickness has to be minimum 150mm.