Improving the Physical and Mechanical Characteristics of Modified Aerated Concrete by Reinforcing with Plant Fibers

An urgent and promising direction in the development of building materials science is the improvement of the quality of non-autoclaved aerated concrete. In view of the obvious disadvantages of non-autoclaved aerated concrete compared to the autoclaved equivalent in terms of technology, it can be significantly improved because of a rationally selected composition and other factors of a recipe-technological nature. The goal of the study was to search for complex compositions and technological solutions aimed at identifying rational combinations of recipe-technological factors as simultaneous modifications of aerated concrete with various additives and dispersed the reinforcement of it with various environmentally friendly and cost-effective types of plant fibers. Fly ash (FA), instead of part of the cement, proved to be more effective than the GGBS additive. The compressive strength (CS), bending strength (BS), and coefficient of construction quality (CCQ) were higher by 4.5%, 3.8%, and 1.7%, respectively, while the density and thermal conductivity (TC) were lower by 0.7% and 3.6%, respectively, compared with aerated concrete modified with ground granulated blast-furnace slag (GGBS). The additional reinforcement of modified aerated concrete with coconut fiber (CF) and sisal fiber (SF) in an amount of 0.6% of the total mass of cement and modifier increases the CS to 15%, BS to 22% and CCQ to 16%. The SF was more effective than the CF. Aerated concrete modified with FA and reinforced with SF showed the highest efficiency. Compared to the control composition without modifiers or fibers, the increase in the CS was up to 40%, BS up to 47%, and CCQ up to 43%, while the decrease in density was up to 2.6%, and TC up to 15%.