A novel development of green UHPC containing waste concrete powder derived from construction and demolition waste

In order to explore the influence mechanism of recycled concrete powder (RCP) on the multi-scale characteristics of UHPC mixtures were investigated. The results indicated that the optimum UHPC mixture prepared with 30% RCP had a relatively low early-age (7-day) autogenous shrinkage strain of 4041.86 mu epsilon, and the highest mechanical properties (Compressive strength of 123 MPa at 28 days). Such values were 5600 mu epsilon and 128 MPa, respectively, for plain UHPC mixture. Although the use of RCP to replace part of the silica fume (SF) reduced the content of hydration products in the matrix, and reduced its compactness, an appropriate amount of RCP (30%) could increase the packing density among particles, thereby improving the polymerization degree of the C-S-H gel. Meanwhile, the environmental benefit of UHPC was also investigated, which also showed that the use of RCP to replace 30% of SF was feasible and sustainable.(c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The influence mechanism of recycled concrete powder (RCP) on the multi-scale characteristics of UHPC mixtures was investigated. It was found that incorporating 30% RCP in UHPC mixtures reduced early-age autogenous shrinkage and improved mechanical properties, indicating that RCP has the potential to enhance the performance of UHPC.