Strain localization of reinforced alkali-activated concrete under corrosion using digital image correlation

Ordinary port land cement (OPC) is one of the most commonly used material in the construction industry. However, its production produces harmful pollutants that largely contribute to global greenhouse emissions, as well as consumes a significant amount of natural resources such as limestone. Studies have found alkali-activated concrete (AAC) to be viable alternative for cement, and one of the greatest advantages of AAC against OPC is it corrosion resistance. In this study, the strain localization of reinforced alkali-activated concrete (AAC) with low-calcium coal fly ash (CFA) and ordinary port land cement (OPC) concrete beams under flexural bending tests with cyclic load has been investigated through digital image correlation (DIC) technique. The strain values obtained from both concrete types were compared and it was concluded that AAC strains are consistently higher than that of OPC Prior to testing the beams, compression tests were conducted on cylindrical samples of the two concrete types wherein it was found that both AAC and OPC are both ductile. Furthermore, the sensitivity of DIC and conventional strain gauges in measuring the strain for both AAC and OPC was investigated, and it was found that both techniques are sensitive for OPC while otherwise for AAC due to strain localization. The strain localization of AAC may be linked to its ductile characterization

Reinforced alkali-activated concrete with induced corrosion

Reinforced concrete comprising of deformed steel bars is the common structural material in construction. The problem of this composite material is the corrosion of deformed steel bars inside the concrete that weakens the structure over time. In this paper, investigation on the two types of reinforced concrete were used: alkali-activated concrete (AAC) and ordinary Portland cement (OPC) concrete beams. In addition, Impressed Current Technique (ICT) was made to accelerate corrosion before performing flexural bending test. The use of a non-destructive test which is the digital image correlation (DIC) technique during the flexural loading test on the two types of beam were considered to monitor the strain values against load. It was concluded that AAC mixture 1:1:2 (coal fly ash: fine aggregate: coarse aggregate) with 12M Molarity and water binder ratio of 0.52 produced the lowest corrosion rate over time for all the beams. In addition, the strain values of the AAC mixture produced ductile behavior with strain softening effect on the third point bending load test where the location of the force was applied. © 2019 International Committee of the SCMT conferences. All rights reserved