FLEXURAL BEHAVIOR OF REINFORCED LIGHTWEIGHT CONCRETE BEAMS MADE WITH ATTAPULGITE AND ALUMINUM WASTE

Lightweight concrete reduces the total dead load of structural elements and seismic loads significantly. This paper presents the production Attapulgite Lightweight aggregate concrete (ALWAC) and its effect on the flexural behavior of reinforced concrete beams. Attapulgite was treated with sodium hypochlorite of 6% concentration for 24 hours. The variable considered was the aluminum waste (AW), used as a fiber, of fraction (0, 0.5 and 1%) by concrete volume. Behavior was investigated in terms of cracking and ultimate load, load-deflection relationship, failure mode, crack patterns and flexural ductility. The mechanical properties of the ALWAC were studied. It was observed that, Attapulgite improves the mechanical properties of concrete when comparing the experimental value with theoretical ones for the reference mixture. AW has a disparate effect on the mechanical properties of ALWAC. The increase in the proportions of AW showed an increase in the cracking load and decrease in the ultimate load by 37.14% and 22.45 %, respectively, at AW of 1%. Experimental value of ultimate load in all beams was higher than the theoretical value (ACI simplified method). AW increases the deflection at the same magnitude of applied load, and reduces the number and propagation of the flexural cracks in beams. All beams exhibited a typical tension failure mode and failed in ductile manner

Durability performance of modified concrete incorporating fly ash and effective microorganism

Environmentally sustainable construction materials with reduced carbon footprint have ever-growing demand worldwide. Based on this factor, some modified cement concrete mixtures incorporated with optimum ratio of fly ash (FA) and effective microorganism (EM) were produced. The strength performance, water absorption, resistance to aggressive environments (sulfuric acid and sulphate) and microstructures of the proposed concretes was evaluated. Four different ratios of FA replacing ordinary Portland cement (OPC) were used to select the optimum composition. The water content was replaced with the EM solution of 5, 10, 15, and 20%. The FA and EM incorporating OPC in the concrete matrix were found to enhance the mechanical and durability characteristics of the modified concretes. The early compressive strength of proposed concrete was enhanced over 30% and the durability was improved against the harsh environment due to the incorporation of OPC with 10% of FA and EM. The optimum concrete obtained with the FA and EM of 10% was asserted to be environmentally beneficial towards less global warming