Structural and life cycle assessments of recycled aggregate concrete beams incorporating industrial hemp fibers

Abstract

As a sustainable concrete material, hemp and recycled aggregate concrete (HRAC) is produced by partial replacement of natural coarse aggregates (NCA) with recycled concrete coarse aggregates (RCA) and industrial hemp fibers. The objective of the reported research was to investigate the structural performance of reinforced concrete beams prepared with HRAC and designed to fail in flexure, shear, or bond splitting modes of failure, and to compare that performance with companion control beams cast with conventional concrete. The significance stems for the fact that no previous research is reported on mixtures using such a combination of hemp fibers and RCA. Test results indicated that HRAC beams with 0.75% volumetric percentage hemp fibers and 50% RCA replacement had comparable peak load capacities to the control beams with no RCA and no fibers, with ±4% difference for all tested modes of failure. Additionally, the fracture energy of the HRAC beam was higher than the control beam by 3.6%, 17.9%, and 14.4% for the flexure, shear, and bond modes of failure, respectively. Moreover, a life cycle analysis (LCA) was considered to compare HRAC mix with conventional concrete mix in terms of the environmental aspects. LCA results indicated that HRAC is a sustainable concrete, specifically with respect to structural performance and lower environmental impact.

Experimental study on mechanical properties of recycled aggregate concrete with polypropylene fiber under combined compression‐shear loading

“…[1][2][3] Recycled coarse aggregate (RCA) is a certain proportion of abandoned buildings broken, cleaned, graded, mixed, and recycled to obtain sustainable materials, as a new building material has great advantages. 4,5 Therefore, the use of RCA in buildings is economical and friendly. It is necessary to develop a RAC that can improve the weak mechanical properties of RCA and replace NAC.…”

“…These studies show that according to the treatment method and content of RCA, it is possible for recycled concrete to be put into engineering applications based on meeting the requirements of strength and durability at the same time, which is also the practice in many countries at present. 4,5 The RCA and RAC can equally replace the NCA and NAC will be the future challenges in the field of civil engineering.…”