Experimental Investigation on self healing concrete mechanical thermal and micro structural studies

Abstract

Concrete is very sensitive to crack formation. As wide cracks newlineendanger the durability, repair is required. However, these repair works newlineraise the life cycle cost of structure, as they are labour intensive. It can newlinedecrease the durability and lifetime of the structure. In order to overcome newlinethis problem, autonomous self-healing mechanism is introduced in the newlineconcrete, which helps to repair the cracks by producing calcium newlinecarbonate crystals, which closes the micro cracks in the concrete. Self- newlineHealing Concrete is one such solution in which those cement-based newlinematerials that repair themselves after the material or structure damaged newlinedue to some sort of deterioration mechanism. The research is carried out newlinein five different phases to achieve the objectives of the study. newlineFrom the first three phases of research, a suitable super absorbent newlinepolymer (SAP) is identified out of two based on the recovery of newlinemechanical properties like compressive, split tensile and flexural strength, newlinevisual observation of cracks before and after self-healing, thermal newlineanalysis and micro-structural characterization. Thermal analysis is newlineconducted using Thermogravimetry Analysis (TGA) and Differential newlineix newlineScanning Calorimetry (DSC) to evaluate the degree of hydration which is newlinethe indirect measurement of cracks after self-healing. newlineIn fourth phase, the optimum dosage of Polyvinyl Alcohol newline(PVA) is found to be 1% when nano-silica is added at 4 wt% of cement newlineto improve the properties of concrete. The flexural behavior of reinforced newlineself-healing concrete beams is compared to that of conventional newlinereinforced concrete beam under four point bending test. In the last phase, newlinethe dosage of costlier nano-silica is reduced from 4 to 1 wt%, cost newlineeffective materials like rice husk ash and sodium bentonite are added by newline10 wt% and 6 wt% of cement respectively with 1.5 wt% being the newlineoptimum dosage of Polyvinyl Alcohol. The closure of cracks is evaluated newlinebased on both visual observation using microscope and digital image newlineprocessing technique using a pseudocode in Matrix Lab