A Study on Chloride Corrosion Resistance of Reactive Powder Concrete (RPC) with Copper Slag Replacing Quartz Sand under Freeze-Thaw Conditions

Jun Li; Xianzhang Liu; Minghao Chen; Lijun Tian; Jiao Liu

doi:10.3390/ma17010212

A Study on Chloride Corrosion Resistance of Reactive Powder Concrete (RPC) with Copper Slag Replacing Quartz Sand under Freeze-Thaw Conditions

Materials (Basel). 2023 Dec 30;17(1):212. doi: 10.3390/ma17010212.

Authors

Jun Li^{1

2}, Xianzhang Liu¹, Minghao Chen¹, Lijun Tian¹, Jiao Liu¹

Affiliations

¹ School of Civil Engineering, Liaoning Technical University, Fuxin 123000, China.
² Liaoning Key Laboratory of Mine Subsidence Disaster Prevention and Control, Liaoning Technical University, Fuxin 123000, China.

Abstract

In order to study the influence of freeze-thaw cycles on chloride ion corrosion resistance of RPC with copper slag (CS) instead of quartz sand (QS), the 28d uniaxial compressive strength (UCS) of CSRPC with a different CS substitution rate was investigated by unconfined compression tests. The electric flux test method was used to study the chloride ion diffusion resistance of CSRPC after freeze-thaw cycles, and the pore size distribution was obtained through the nuclear magnetic resonance (NMR) method. Then, a mathematical relationship between the chloride ion diffusion coefficient and the pore fractal characteristic parameter T was established to study the effect of freeze-thaw cycles on chloride ion diffusion. Finally, SEM/EDS, XRD, and DTG methods were combined to study the influence of the distribution of Friedel's salts generated after freeze-thaw cycles on chloride ion diffusion in CSRPC. The results indicate that CS has a micro aggregate effect and pozzolanic activity, which can effectively improve the chloride ion diffusion resistance of CSRPC after freeze-thaw cycles. In addition, the electric flux of CSRPC decreases with the increase in freeze-thaw cycles, and the chloride diffusion coefficient is closely related to the pore fractal dimension.

Keywords: RPC; chloride ion diffusion; copper slag; freeze–thaw cycles.

Grants and funding

This research was supported by the Liaoning Provincial Department of Education Foundation Project “Pioneering Research on Key Technology of Copper Slag-Based Assembled Road Base Block Connection” (Project No. LJKMZ20220703).