Study on properties of basalt fiber reinforcing reactive powder concrete under different curing conditions

Abstract

The influence of basalt fiber (BF) on the mechanical properties of reactive powder concrete (RPC) under different curing systems was studied. Three curing systems were adopted: natural curing (NC), standard curing (SC) and combined curing (CC). The design formulas for compressive and splitting tensile strength of basalt fiber reactive powder concrete (BFRPC) were established. The hydration process and strength changes of BFRPC under different systems were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The test results showed that the CC was better than the SC and slightly better than the NC, while the hydration of the CC was insufficient in the later stage, and the growth rate was significantly lower than the SC or NC. BF showed good compatibility with the matrix and was closely bonded. BF with proper content and the matrix were pressed together to improve the mechanical properties of BFRPC, while an excess of BF content would cause weakened areas and reduce strength. In comparison to plain RPC (with BF content of 0 %), the maximum increase rates of 28-day compressive strength of BFRPC under NC, SC and CC systems were 22.8 %, 18.4 % and 8.9 %, respectively. As for 28-day splitting tensile strength, the maximum increase rates became 74.5 %, 66.5 % and 49.67 %, respectively. Considering the economy and practicability of the actual project, the strength prediction formula of BFRPC was put forward to facilitate its popularization and application.

Keywords

• Reactive powder concrete
• Curing system
• Mechanical strength
• Microstructure
• Prediction formula