Evaluation of Tensile Strength and Durability of Microbial Cement Mortar

Abstract

In this research, an attempt has been made to study the effect of adding the micro-organisms in cement mortar on its tensile strength. In addition to evaluating the durability of cement mortar with and without micro-organisms by studying the deterioration in tensile strength after sulfuric acid (H2SO4 with 6% concentration) attack.The experimental work included casting four mixes (denoted by: case 1, case 2, case 3, case 4 and the control mixes) which differ according to the way of adding micro-organisms, casting water, curing water (or both).Each mix contains three cylindrical specimens except case 4 and the control mix which contain six cylinders each. It was found that, when adding micro-organisms; the tensile strength was increased (i.e. all mixes gave a higher percentage of tensile strength) as compared with that of the control mix.The results revealed that for the microbial cement mortar (case 4), the percentage of deterioration in tensile strength, was smaller [after the sulfuric acid H2SO4 (6% concentration) attacked the samples] than that of the control mix. It was also found that the effect of using bacterial additives on the percentage of increasing in tensile strength of cement mortar (case4 & control) is increased after sulfuric acid (H2SO4: 6% concentration) attack.