Tensile behavior of synthetic fiber-reinforced strain-hardening cement-based composite (SHCC) after freezing and thawing exposure

Strain-hardening cement-based composites (SHCC) are distinguishable from ordinary fiber-reinforced cement-based composites (FRCC) because they have a tensile stress versus strain behavior that exhibits pseudo strain-hardening accompanied by multiple cracking. SHCC materials have become an appealing possibility as building materials in a wide variety of civil engineering projects. Freeze–thaw cycles pose a serious problem for the successful application of SHCCs in cold environments. This paper describes the direct tensile properties of SHCC before and after rapid freezing and thawing exposure in a controlled environment. The primary objective of this research is to provide comprehensive laboratory data on the influences of freeze–thaw cycles on the tensile performance of SHCC materials. The SHCC specimens used in the present study were reinforced with polyvinyl alcohol (PVA) and ultra-high molecular weight polyethylene (PE). The total percentages of fiber reinforcement in the SHCCs with PVA and PE were 2.0% and 1.5%, respectively. Cylindrical SHCC specimens with a diameter of 100 mm and height of 200 mm were made and tested for direct tensile strength. The freeze–thaw testing used in the study followed the recommendations found in Procedure A (frozen and thawed in water) of Korean Industrial Standard (KS) F 2456, which is similar to the ASTM C 666 Procedure A, and included 200 freeze–thaw cycles. The test results for freezing and thawing within 200 cycles indicated that the freeze–thaw cycles had a slight effect on the tensile response of the SHCCs. By increasing the number of freeze–thaw cycles, the tensile strength of the SHCC materials under monotonic and cyclic axial loading increased, while the tensile strain capacity decreased. This phenomenon is noticeable for PVA-SHCC materials.

Research highlights► PE and PVA fibers reinforced strain-hardening cement-based composites (SHCCs). ► Tensile properties of SHCC cylindrical specimens after 200 cycles of freezing and thawing actions. ► Direct tensile strength of the SHCC materials under monotonic and cyclic loading increased. ► The tensile strain capacity decreased.