DefinePK

Abstract

Bio-concrete or “Bacterial Concrete” which can be produced by embedding bacteria in the concrete that are capable to precipitate calcite constantly and investigate its ability of remedy the network of cracks formed under repeated loads , its ability to reduce cracks impact on the concrete performance and improve its mechanical properties. Slabs are one of the most important parts of the structural construction, in which the thickness is small compared with the other dimensions and they sustain loads normal to their planes so in this study eight one way thick slabs with dimensions (1450*500*120) mm have been casted with two ways of bacteria addition (direct addition with mixing water and encapsulated bacteria in breaking bricks stone LWA particles) , six of them was tested in two stages to find out the effectiveness of bacteria in repairing the cracks and regain the performance of concrete. The experimental result showed that the bacterial direct addition specimen increase the compressive strength by about (11.8%) for bacterial direct addition, slabs were tested first under repeated loads up to eight cycles all the slabs with bacterial addition showed improvement in performance in varying degrees reached (4.85%) for first cracking load and (4.89%) for load of the eight cycle , and the specimen has been lifted in water for 28 days, than the second stage was started which was monotonic test , the main purpose is to investigate the bio-concrete ability of regain its performance beside its ability of healing the crack and increase the concrete sustainability, all specimen with both types of bacterial addition showed improvement in performance that’s reached (111%) for first crack loading and (5.63%)for ultimate load, Three-dimensional nonlinear finite element analysis has been used to conduct the numerical investigation of the general behavior of thick slabs. ANSYS (Version 15.0) computer software was used in this work, the comparison between the experimental and numerical results showed a reasonable agreement (to cycle eight), and the solution of slab under repeated load until failure has been completed by using numerical solution.