No abstract

The objective of this research study is to demonstrate the axial compressive behavior of GRFC columns by fabricating five circular columns (1150 mm high and 250 mm in cross-section) and testing them under axial concentric loading. Two different kinds of fibers, that is, polyvinyl alcoholfibers (PVA) and polypropylene fibers (PPF) were incorporated into the concrete. Two types of transverse confinement (GFRP hoops and GFRP spirals) were provided. The efficiency of GFRP hoops was explored by providing them at the spacing of 75 mm, 150 mm, and 250 mm, respectively. The efficiency of GFRP spirals was examined by keeping the spacing of 38 mm and 75 mm, respectively. The GRFC columns confined with GFRP spirals portrayed higher axial strength and higher ductility indices. Furthermore, an extensive finite element modeling (FEM) was performed by considering the effect of hybrid fibers using a modified concrete damaged plastic (CDP) model. The proposed FEM captured the axial response and cracking behavior of GRFC columns with high accuracy. This study also proposed a new empirical model for capturing the axial strength of GRFC columns by considering the influence of GFRP bars and lateral confinement of GFRP hoops/spirals.

No abstract

This study investigated the effect of elevated temperature on the mechanical, physical and durability properties of normal strength concrete, modified with bentonite. The bentonite concrete was cast by substituting cement with bentonite content in proportions of 5, 10 and 15% by weight. Mechanical tests were conducted (compressive and splitting tensile strength). Furthermore, durability performance (mass loss and sorptivity) and specimen properties (elastic modulus, stress–strain behaviour, ductility and energy absorption) were evaluated and discussed. The results demonstrated that samples incorporating bentonite showed better fire endurance than the control mix. The inclusion of bentonite in concrete decreased the mass loss of the specimens exposed to high temperatures. The performance of bentonite concrete was better in terms of mechanical behaviour (compressive and tensile strength) than that of conventional concrete, and it had high resistance to water absorption. Higher ductility and energy absorption capacity were observed for the concrete specimen containing bentonite than its counterpart control specimens.

No abstract