Utilization of Jebel Marra Volcanic Ash as Low Cost Material in Concrete Hollow Blocks in Darfur, Sudan

Concrete hollow blocks (CHB) have an important place in modern building industry, and although the CHB is considered a better alternative to fired bricks from ecological economical points of view, however, its prices are still high, since main cost-factor ordinary Portland cement (OPC). This study mainly focusing on utilization volcanic ash (VA) Jebel Marra as low cost material for CHB. In this VA sample (Al-malam area) was investigated physical chemical properties, different substitution levels 10, 20, 30, 40, 50% OPC with pozzolanas were tested. Combined aggregates locally available sand stone also tested their value fineness modulus. Then potential use these materials implemented blends mix ratios. The results analysis showed compliance international specifications. strength activity index containing 20%VA weight at 28 days 87%. If consider 3.5 MPa minimum compressive load bearing required by Indian standard, it can be concluded that used successfully level up 40%, 30%, 20%, binder ratio volume 1:6, 1:7, 1:8, respectively, subsequent reduction 34, 26, 17%, addition, increasing achieved using high pressure making machine.