MECHANICAL PROPERTIES OF ENVIRONMENTALLY FRIENDLY GREEN CONCRETE MADE WITH NATURAL AND RECYCLED FINE AGGREGATES

Abstract

Extensive research efforts have been undertaken in the past to utilize several kinds of recycled fine aggregates to produce environmentally friendly and more sustainable concrete. In Thailand, various types of bricks, including fired clay hollow, fired clay solid, and hydraulically pressed cement-clay bricks, are manufactured for constructing low-rise buildings. There is an urgent requirement to employ recycled fine aggregates made from these bricks to mitigate the disposal and demolition waste generated by the brick industry. At present, the utilization of waste bricks of Thailand's origin as fine aggregates in concrete is yet to be investigated. Three types of fine recycled brick aggregates were utilized to create sustainable concrete. The recycled fine brick aggregates were substituted for natural fine aggregates at proportions of 0%, 10%, and 20% to formulate the concrete mixes. Furthermore, three distinct types of tests—compression, splitting, and flexural tests—were conducted to evaluate the mechanical properties of the concrete. The compressive and splitting tensile strengths increased with the replacement ratio of recycled aggregates. Notably, up to 51% and 80% improvements in the compressive and splitting tensile strength were observed, corresponding to 20% replacement proportions, respectively. However, the flexural strengths exhibited were attributed to the type of waste brick, with a maximum improvement of up to 22%. Moreover, the water absorption tendency was reduced by incorporating recycled fine aggregates in concrete. The current work aimed only at examining the strengths of recycled brick aggregate concrete. Therefore, future works are recommended to investigate the complete stress vs. strain constitutive relationships of this concrete as well as its flowability.