Abstract:
Jehangira bentonite deposits occur at 33o59’56” latitude and 72o12’47” longitude in the Survey of Pakistan topographic sheet 43 C/1. These deposits are spread over an area of 26 Sq. km and average depth of the bed is almost 3.5m. Chemical analysis shows that Jehangira bentonite contains high amount of silicon, ferric and aluminium oxides as main components, which have the characteristics to react with free lime made available as the by-product of cement hydration. This research study is carried out to evaluate the feasibility of use of Jehangira bentonite, in production of concrete, as partial replacement of cement.
The main variables in this research study are the amount of bentonite and dosage of superplasticizer. The parameters which are kept constant are the amount of cementitious material equal to 460 Kg/m3 and water to cementitious material ratio equal to 0.55.
Test results revealed that mixes associated with bentonite, showed slightly lower compressive strength than control mix (CM). However, it showed excellent resistance against acid attack. Water absorption was found minimum for mix containing 20 per cent bentonite as partial replacement of cement (20BC). Moreover, reactivity index for 20BC was found to be within the standards laid by ASTM C618.
