Wet casting of multiple mix horizontally layered concrete elements

Functionally graded concrete, where multiple mixes are layered in structural elements, is a promising technology for minimising cement use. However, a challenge when fabricating wet-on-wet graded concrete is the control of the fresh state deformations of multiple mixes cast into the same mould. Horizontally cast elements with two different concrete mix layers were investigated to ascertain the influence of mix density, workability and layer sequence on the intended material placement. Horizontal layers were achievable unless the workability of the top layer was much stiffer than that of the bottom, or the top layer was denser and both mixes were fluid. The findings underpin opportunities for the exploitation of lower carbon materials and cement efficiency. (C) 2020 Elsevier Ltd. All rights reserved.