The effect of cement and Air Entrainment Admixture (AEA) on engineering properties of concrete in irrigation canals lining

In this research, the effect of cement content and AEA on engineering properties of irrigation canal linings were studied. In this context, 9 different concrete mixtures (treatments) were designed and fabricated using 3 levels of AEA ; 0, 0.01, and 0.03 percent by weight of cement and 3 levels of cement content; 300, 350 and 400 kg/m3. Various experiments included: determination of total air, density and determination of the amount of slump on fresh concrete and density, porosity, compressive strength and electrical resistance tests on hardened concrete samples of all mixtures. The results of experiments on fresh concrete showed that as the AEA increased , the slump of fresh concrete and total air volume also increased whereas concrete density decreased. The results of experiments on hardened concrete indicated that addition of 0.03 percent by weight of bubble making substance to concrete mixture to any of 3 cement samples, resulted in reduction of density, compressive strength and electrical resistance. According to the existing indicators, the cement content of 300 kg / m3 (with and without AEA) is not a suitable option for irrigation canals lining. In irrigation canals, it is necessary to provide the minimum compressive strength in this regard concrete mixtures of 350 (without weathering) and concrete mixtures of 400 kg / m3 (without AEA) and 0.01% of AEA cement weight was found to be suitable option. For the concrete lining in cold regions, the best option for ensuring the compressive strength parameter and the durability against frost is concrete mix with a weight of 400 kg / m3 and 0.01% AEA by cement weight.