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. (C) 2011 Elsevier B.V. All rights reserved.