Use of Bentonite and Organobentonite as Alternatives of Partial Substitution of Cement in Concrete Manufacturing

In order to study the capacities of a new occurrence of Brazilian clay samples as partial replacements of cement, a bentonite sample was selected for utilization in the natural and modified forms for present study. The natural bentonite (BBT) was modified by anchorament of 3-aminopropyltrietoxisilane (BBT APS ) and 3,2-aminoethylaminopropyltrimetoxisilane (BBT AEAPS ) in the surface of component minerals of bentonite sample. The original and organo-bentonite samples were characterized by elemental analysis, scanning electron microscopic and textural analyses. The values of micropore area were varying from 7.2 m 2 g −1 for the BBT to 12.3 m 2 g −1 for the BBT AEAPS . The bentonite samples were characterized by the main variable proportion of bentonite in the natural and intercalated forms (2, 5, 10, 15, 20, 25, 30, and 35 % by weight of cement) in the replacement mode whiles the amount of cementations material. The workability, density of fresh concrete, and absorption of water decreased as the substitution of ordinary Portland cement by perceptual of natural and modified bentonite increased. The results reveal that workability decreased with decrease of the amount of natural bentonite in the concrete, same behavior is observed for bentonite functionalized, varying from 49 to 28 mm. The energetic influence of the interaction of calcium nitrate in the structure of blends was determined through the calorimetric titration procedure.