This study compared the physical and mechanical properties of river sand concrete with quarry dust concrete. The constituent materials were batched by weight. The water-cement ratio and mix ratio selected for the experimental investigation were 0.55 and 1:2:4, respectively. The specimens were cured for 7, 14, 21 and 28 days. Slump, density and compressive strength tests were carried out. The results showed that river sand concrete had greater density and compressive strength than quarry dust concrete for all curing ages. At 28 days of curing, river sand concrete exceeded the target compressive strength by 36%, whereas quarry dust concrete was less than the target compressive strength by 12%. Both river sand concrete and quarry dust concrete for the selected water/cement ratio and mix ratio are suitable for non-structural applications and lightly-loaded members where high strength is not a prerequisite.

Concrete is the most popular man-made construction material in the world. However, there is a growing need to use sustainable recycled materials as replacement of conventional aggregate in concrete due to environmental and economic considerations. A possible solution to the waste management problem of agricultural and aquaculture by-products is to use them as an alternative aggregate in concrete. Agricultural and aquaculture by-products such as palm kernel shell, coconut shell, date seed, rubber shell, corn cob, rice husk, periwinkle shell, mussel shell, oyster shell, cockle shell and scallop shell have been used in experimental investigations as partial or full replacement of conventional aggregate in concrete. This paper is a literature review of recent developments in the utilisation of agricultural and aquaculture by-products as aggregate in concrete. Physical and mechanical properties of the by-products, as well as properties of by-product aggregate concrete in fresh and hardened states, are discussed. Trends, developments and possible barriers in using agricultural and aquaculture by-products as aggregate replacement materials in concrete are highlighted. It is recommended, among others, that detailed research on durability properties of concrete containing agricultural and aquaculture by-product aggregates should be carried out.

Comparative analysis of mechanical properties of palm kernel shell concrete with periwinkle shell concrete is presented in the paper. The binder and fine aggregate were Ordinary Portland cement and river sand, respectively, while potable water was used for mixing and curing. The constituent materials were batched by weight. Concrete mix ratio was 1:2:4 and water/cement ratio was 0.5. Three groups of concrete mixes containing different coarse aggregates were tested: 100% palm kernel shells, 100% periwinkle shells, and 100% granite as control. Tests were carried out for bulk density and compressive strength of the concrete cubes at 7, 14, 21, and 28 days curing, respectively. The results revealed that for all curing ages, palm kernel shell concrete had lower bulk density and lower compressive strength than periwinkle shell concrete. The bulk density and compressive strength of the 28-day palm kernel shell concrete were 1840 kg/m3 and 14.02 N/mm2, respectively, those of periwinkle shell concrete were 1936 kg/m3 and 16.90 N/mm2, while those of granite concrete were 2496 kg/m3 and 25.95 N/mm2, respectively. Both palm kernel shell concrete and periwinkle shell concrete satisfied the bulk density and compressive strength requirements for lightweight aggregate concrete.

An experimental study of recycled aggregate concrete (RAC) using recycled coarse aggregate (RCA) is reported. The RCA was obtained from construction and demolition waste (C&DW) and used as full replacement of natural coarse aggregate (NCA) for production of RAC. Crushed granite was used as NCA, while crushed concrete rubble from a demolished concrete building was used as RCA. Two groups of concrete mixtures were tested: 100% NCA as control and 100% RCA. Bulk density and compressive strength tests of concrete cubes were conducted at 7, 14, 21, and 28 curing days respectively. The results showed that bulk density and compressive strength of natural aggregate concrete (NAC) were higher than those of RAC for different ages of concrete. The bulk density and compressive strength of the 28-day RAC were 2,328 kg/m

Purpose: The purpose of this paper is to analyze the inelastic buckling of a rectangular thin flat isotropic plate subjected to uniform uniaxial in-plane compression using a work principle, a deformation plasticity theory and Taylor–Maclaurin series formulation. Design/methodology/approach: The non-loaded longitudinal edges of the rectangular plate are clamped, whereas the loaded edges are simply supported (CSCS). Total work error function is applied to Stowell’s plasticity theory in the derivation of the inelastic buckling equation. Mathematical formulation of the Taylor–Maclaurin series deflection function satisfied the boundary conditions of the CSCS rectangular plate. The critical inelastic load of the plate is then derived by applying variational principles. Findings: Values of the plate buckling coefficient are calculated using various values of moduli ratio for aspect ratios ranging from 0.1 to 1.0, in intervals of 0.1. The accuracy of the proposed technique is validated by comparing the results obtained in the present study with solutions from a previous investigation. The percentage differences in the values of the buckling coefficient ranged from −0.122 to −4.685 per cent. Originality/value: The results indicate that the work principle approach can be used as an alternative approximate method for analyzing inelastic buckling of rectangular thin flat isotropic plates under uniform in-plane compressive loads.