Mechanical performance of basalt and PVA fiber reinforced hybrid-fiber engineered cementitious composite with superimposed basalt fiber content

Abstract

• PVA/basalt HF-ECC with multiple cracking behavior was achieved by superimposition of basalt fiber. • Increasing basalt fiber superimposing content improved overall strength of PVA/basalt HF-ECC. • The advised optimal superimposing volume fraction of basalt fiber is 0.8%. • The effect of basalt fiber on tensile strain capacity was analyzed by micro-mechanical analysis. The large-scale application and popularity of engineered cementitious composites (ECC) is hindered by the relatively high price and increased CO 2 footprint of PVA fiber. PVA and basalt fiber reinforced hybrid-fiber ECC (PVA/basalt HF-ECC) is a promising way to deal with such drawbacks. Hence, this study focused on the influence of basalt fiber superimposing content on the properties of PVA/basalt HF-ECC. Compressive tests indicated basalt fiber could elevate compressive strength and its corresponding strain, the obtained maximum values were 46.37 MPa and 0.47 % as basalt fiber content increased up to 1.2 %. Tensile tests showed that first cracking strength and ultimate tensile strength increased up to 6.62 MPa and 7.85 MPa as basalt fiber content increased up to 1.2 %. Although tensile strain capacity continuously decreased to 0.62 %, all specimens showed multiple cracking behavior due to the superimposed performances derived from PVA and Basalt fibers. Mercury intrusion porosimetry test showed volume fraction of large capillary pore that influences strength decreased up to 31.65 % when basalt fiber content increased to 1.2 %. Based on test results, predicting equations of mechanical properties were proposed by curve fitting and showed good agreement with test results. Micro-mechanical analysis was conducted based on modified crack bridging model, and its results further interpreted change mechanism of tensile strain capacity. This study explores the feasibility of developing PVA/basalt HF-ECC by basalt fiber superimposition and facilitates the popularity of ECC.