Impact of organic carbon on hardened properties and durability of limestone cement concrete
By Ahmed M. Diab and Ismail A. Mohamed and Ali A. Aliabdo
Published in Construction and Building Materials
2016
Abstract
In this paper, the effect of organic carbon in ground limestone on the properties and behavior of Portland limestone cement (PLC) concrete in normal and aggressive medium was studied. Three different sources of limestone with total organic carbon of 0.94, 0.48 and 0.18% were considered, the cement replacement ratios were 0, 10, 15, 20 and 25% by weight and water to binder ratio was 0.55. Mechanical properties, \XRD\ and \TGA\ experiments were conducted to evaluate the effect of the previous variables on hardened properties of concrete and hydration process of cement paste. Corrosion rate and polarization resistance of reinforcing \PLC\ concrete specimens immersed in 5.0% sodium chloride solution for 12 months were measured using potentiodynamic polarization resistance technique. The sulfate resistance of \PLC\ concrete specimens was also investigated. Concrete specimens exposed to wetting and drying cycles in 5% magnesium sulfate solution for 18 months were tested. \SEMs\ of limestone cement paste after magnesium sulfate exposure were performed. The results emphasize the essential role of organic carbon on the properties and behavior of \PLC\ concrete for both normal and aggressive medium especially at high ratios of cement replacement with limestone.