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This research proposed bacteria-treated concrete, which is highly desirable because the mineral precipitation induced from microbial activities is pollution free and natural. This study investigates the effects of Bacillus Licheniformis, Bacillus Cohnii and mixed bacteria on compressive strength, ultrasonic pulse velocity test, rapid chloride penetration test, microstructural analysis and bacteria cell concentration of 10 5 cell/ml of normal and selfcompacting mortars made with and without fly ash for 7 and 28 days. With self-compacting mortar, the compressive strength of Bacillus Licheniformis improved by 30.3 % and by adding Bacillus Cohnii in 28 days, the ion penetration value decreased. Finally, it was observed that the deposition of calcium carbonate in mortar improved compressive strength using SEM-EDS and XRD with compound polymorphisms of calcite, vaterite, quartz, and Hautirite.

Shear cracking behaviour of fibrous self-compacting concrete of normal and high strength grade (M30 and M70) is presented here. Two stirrup diameters (6mm ∅ and 8 mm ∅) with a constant steel fiber content of 38 kg/m3 (0.5% by volume of concrete) were selected for the present study. The size of the beam was fixed at 100x200x1200mm. The clear span of the beam 1100mm, was maintained throughout the study. A total of 16 shear-deficient beams were tested under three point loading. Two stirrup spacing (180mm and 360 mm) are used for the shear span-to-depth ratio (a/d = 2). Investigation indicates that initial cracking load and ultimate load increased as the area of shear reinforcement increased by increasing the diameter of stirrup. It was also noted that the failure mode was modified from brittle shear failure to flexural-shear failure in the presence of fibers. The mechanical behaviour of SFRSCC was improved due to the combined effect of stirrups and steel fibers. The stiffness, toughness, and deflection of the beams increased when compared to SCC beams without fibers. The experimental results were compared with existing models available in literature, and the correlation is satisfactory.

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