This paper discusses the recycling system for concrete needed due to environmental and resource preservation issues. Construction and demolition waste is one problem faced in the construction site. One feasible solution to overcome this problem is by utilizing construction and demolition waste as a recycled coarse aggregate (RCA). This study aims to observe concrete mechanical properties using RCA with surface treatment. Acrylic-based material is used to treat the surface of recycled coarse aggregate (RCA) by spraying it from two sides. It is found that the recycled aggregate with surface treatment may reduce water absorption from 7.96% to 2.96%. In addition, the concrete using RCA with surface treatment may improve the compressive strength, modulus of elasticity and split tensile strength.
Engineered Cementitious Composites (ECC) exhibit high ductility accompanied by multiple narrow cracking behavior under uniaxial tension. The study experimentally investigated the influence of sodium lignosulfonate and high volumes of fly ash (HVFA) on the properties of fresh and hardened ECC, with the experimental variables including the amounts of fly ash, polyvinyl alcohol (PVA) fibers, and sodium lignosulfonate. The test results were discussed extensively in terms of the initial and final setting times, compressive and tensile behavior, and drying and autogenous shrinkage. The results indicated that the initial and final setting times of ECC were increased along with the sodium lignosulfonate content of up to 1%. The drying shrinkage development was governed by the first 14 days. In addition, the major autogenous shrinkage developed for more than 28 days. The amounts of fly ash, PVA fibers, and sodium lignosulfonate considerably impacted the autogenous shrinkage. Moreover, it was found that the dosage of sodium lignosulfonate at 0.5% of the weight of Portland cement optimally reduced the shrinkage and enhanced the tensile strain capacity for ECC.
A building whose functions are converted in which their volumes are improved, for example, a four-story building transformed into a five-story building, resulting in a dead load improvement of its structural self-weight, obviously requires strengthening in order to avoid the possibility of structural failures. This paper focuses on a nonlinear finite element analysis conducted using the ATENA program on T-section reinforced concrete beams strengthened in the negative moment region with wire ropes and an addition of steel rebars at the compression block. The results are then compared with the results of the previously conducted experiments. The specimen models consist of control beams (BK), strengthened beams with wire ropes at the tension block (BP1), and strengthened beams with wire ropes at the tension block and steel rebars at the compression block (BP2). The results show that the ratios of the load-carrying capacity against those of the experimental results are 1.25, 1.23, and 0.89 respectively for BK, BP1 and BP2. The effective stiffness ratios to those of the experimental results are 1.45, 1.15, and 1.86, while the ductility index ratios against the experimental results are 1.11, 0.63, and 1.01 respectively for BK, BP1, and BP2. The crack patterns of the nonlinear finite element analytical results revealed that all specimen models experience flexural failure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.