Properties of Plain and Blended Cement Concrete Immersed in Acidic Peat Water Canal

Reinforced concrete structures exposed to the acidic environment, such as acidic soil, agricultural building, industrial acid, are unavoidable in practice. Structures and infrastructures in acidic environment are usually have durability problems related to degradation of concrete cover and corrosion of steel reinforcement. Acidic soil such as peat, contains organic humic acids that can retard cement hydration process, and potentially reduce the concrete integrity after continuous exposed to the environment. This research is aimed to investigate concrete degradation when subjected to peat water by direct field exposure in water canal. The specimens were made from Ordinary Portland Cement (OPC), Portland Composite Cement (PCC) and OPC replaced with 10% (by cement weight) Palm Oil Fuel Ash (OPC POFA). Those plain and blended cement specimens were cast and cured in water pond in laboratory, then immersed in peat water canal up to 120 days. Compressive strength, tensile strength and porosity of specimens were measured at 28, 91 and 120 days. After 120 days of immersion, compressive and tensile strength reduction, and porosity increase were seen for the OPC specimens. The PCC and OPC POFA specimens performed a gradual increase in both compressive and tensile strength, and reduction of porosity with the exposure period. The results indicated that cement type had significant effect on concrete properties exposed to the peat water directly. The test results showed that the PCC samples are more chemically resistant to acid attack in peat water, followed by the OPC POFA samples and finally the OPC samples after subjected to acidic peat water canal.