Open Access

ARTICLE

Effect of Recycled Mixed Powder on the Mechanical Properties and Microstructure of Concrete

Chao Liu^1,2,*, Huawei Liu^2,*, Jian Wu¹

1 Shaanxi Key Laboratory of Safety and Durability of Concrete Structures, Xijing University, Xi’an, 710123, China
2 School of Civil Engineering, Xi’an University of Architecture and Technology, Xi’an, 710055, China

* Corresponding Authors: Chao Liu. Email: ; Huawei Liu. Email:

(This article belongs to the Special Issue: Recycled Concrete Towards a Sustainable Society)

Journal of Renewable Materials 2022, 10(5), 1397-1414. https://doi.org/10.32604/jrm.2022.018386

Received 21 July 2021; Accepted 15 September 2021; Issue published 22 December 2021

Abstract

In this paper, recycled bricks and recycled concrete were applied to prepare eco-friendly recycled mixed powder (RMP) cementitious material, as a supplementary to replace conventional cement for improve the recycling of construction and demolition waste. Based on the effect of cementitious materials on the hydration of silicate cement, the effects of RMP on the workability, mechanical properties and microstructure of recycled mixed powder concrete (RMPC) with the different replacement ratios and the 8:4 and 6:4 mixing ratio of recycled brick powder (RBP) and recycled concrete powder (RCP) were investigated. The results showed that the fluidity of the mix decreased with increasing of the replacement ratio and the mixing ratio of RBP and RCP, but the influence of the fluidity was smaller within 15% replacement ratio. As the replacement ratio increases, the internal pore structure of RMPC tends to be loose and porous, which exhibits a significant pore volume distribution characteristic. The number of large capillaries was considerably increased at replacement ratio of 45%. The 7 d compressive strength of RMPC was slightly lower than that of ordinary concrete. The compressive and splitting tensile strengths of RMPC at 28 d increased by 4.2% and 10.1%, respectively, with increasing curing age at 15% replacement ratio and 6:4 mixing ratio. The RMPC mechanical strengths with RBP and RCP at the mixing ratio of 6:4 was higher than those of 8:2. Finally, a basis for the recycling of RBP and RCP in the construction industry can be provided by the results of this study.

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