Effectiveness of using pozzolanic material for concrete canal blocks in tropical peatland

The canal blocking system is commonly applied in to control water table in peatland recovery during prolonged dry weather in tropical peatland. The canal blocking is an effective strategy in preventing peat fire in many areas in Riau Province. Various local material such as earth, timber, sand, stone, rock, and concrete have been used in canal blocks. The concrete canal blocks are usually built at the river downstream and need to be stronger, durable and stable than other materials. Tropical peatland is a highly organic and highly acidic environment that could damage and reduce concrete structures service life in the long term. In this research, strength properties and porosity were evaluated to indicate the effectiveness of using pozzolanic material to increase resistance to the acid attack in concrete canal blocks. The concrete was produced by incorporating 10% Palm Oil Fuel Ash (OPC POFA) as a pozzolanic material from biomass to replace the Ordinary Portland Cement (OPC) cement content. The locally available commercial Portland Composite Cement (PCC) that contains pozzolanic material was also studied. The OPC concrete was used as a control mix with a target strength of 35 MPa. Specimens were cast and cured for 28 days in a laboratory water pond before subsequently placed in peat water canal nearby Rimbo Panjang Regency in Riau Province. The reduction rate in compressive strength, tensile strength, Young's Modulus of Elasticity, and porosity of concrete at 28, 91, 120 and 150 days were determined. Results show that the inclusion of pozzolanic material in concrete has increased the compressive strength, tensile strength, Young's Modulus of Elasticity and reduced the porosity. PCC and OPC POFA had better performance than the OPC concrete after immersed in the canal up to 150 days. Hence, it can be concluded that the pozzolanic material is effective in improving properties and acid resistance of concrete canal blocks in tropical peatland. (paper)