Enhancing strength of concrete through minimized porosity

Abstract

Porosity in concrete is a major defect that can be experienced after curing wet concrete mixtures which adversely affects the strength of concrete. Among the methods used to reduce porosity in concrete, still there is room for conceptualizing a methodology for further evolvement. Vacuum infusion technique was used to pump out entrapped air during the construction of boats using Ferrocement. This study focuses on checking the feasibility of applying the same technique to minimize the porosity of concrete. Grade 30 concrete samples were made using two different water cement ratios and aggregate sizes. Test cubes were cast using these concrete mixes and were subjected to infusion for two different durations. The samples were cured and tested for compressive strength at 7 and 28 days. Results revealed that the vacuum infusion technique can lead to significant increment in compressive strength. The results of porosity test show up to 4% reduction in porosity of samples subjected to infusion. Scanning Electron Microscope (SEM) test results also revealed a highly compacted microstructure in the samples. Therefore, it is evident that the vacuum infusion method can effectively reduce the porosity of concrete. Further, this technique can be developed to be used in precast concrete.