249 / 2022-06-17 22:58:11

Development of Basalt-fiber ECC

Basalt fiber;,Engineered Cementitious Composites,Mechanical properties,Crack pattern,Multiple Cracks

Fiber plays a key role in the mechanical properties of Engineered Cementitious Composites (ECC), a new generation of fiber-reinforced concrete with excellent ductility and exceptional crack control capability. However, ECC loses its high ductility when exposed to fire, as the synthetic fibers typically used in ECC melt resulting in a loss of crack-bridging ability in elevated temperatures. In this study, the feasibility of using basalt fiber, an inorganic fiber with high-temperature resistance, to develop ECC is investigated experimentally. the Basalt Fiber Engineered Cementitious Composites (BF-ECC) with different amounts of basalt fiber and matrix ingredients were designed. Compressive and uniaxial tensile tests were conducted to characterize the macro-scale mechanical properties. The underlying mechanisms of the crack pattern are investigated from the perspective of meso-scale relationship of fiber bridging and crack opening displacement.



The results show that basalt fiber reinforced ECC (BF-ECC) exhibits a very unique strain-hardening and multiple-cracking behavior when compared with typical ECCs. Extremely tight and densely distributed cracks are exhibited on BF-ECC specimens after tensioning into the strain-hardening regime. The average crack width is less than 8 μm, about one order of magnitude smaller than typical ECCs prepared with PVA, PP or PE fibers. The tensile stress-strain curve of BF-ECC is uniquely smooth. Stress drops during strain-hardening in ECC is found to scale linearly with crack width. The almost imperceptible stress drops in BF-ECC is due to its extremely tight crack width. Increasing cement content (from 10% to 20%) in the studied BF-ECC leads to an increase in the first cracking strength of (from 1.86 MPa to 2.44 MPa) and the ultimate tensile strength (from 3.29 MPa to 3.51 MPa), but a decrease in the tensile strain capacity. As expected, the ultimate tensile strength and tensile strain capacity of BF-ECC both increase with fiber content.



This work paves the way for further developing ECC with high-temperature resistance.