Choi Won-Chang, Yun Hyun-Do
Department of CAAE Engineering, North Carolina A&T State University, Greensboro, NC, 27411, USA.
Department of Architectural Engineering, Chungnam National University, Daejeon 305-764, Republic of Korea.
ScientificWorldJournal. 2013 Nov 24;2013:418734. doi: 10.1155/2013/418734. eCollection 2013.
High-performance fiber-reinforced cement composites (HPFRCCs) are characterized by strain-hardening and multiple cracking during the inelastic deformation process, but they also develop high shrinkage strain. This study investigates the effects of replacing Portland cement with calcium sulfoaluminate-based expansive admixtures (CSA EXAs) to compensate for the shrinkage and associated mechanical behavior of HPFRCCs. Two types of CSA EXA (CSA-K and CSA-J), each with a different chemical composition, are used in this study. Various replacement ratios (0%, 8%, 10%, 12%, and 14% by weight of cement) of CSA EXA are considered for the design of HPFRCC mixtures reinforced with 1.5% polyethylene (PE) fibers by volume. Mechanical properties, such as shrinkage compensation, compressive strength, flexural strength, and direct tensile strength, of the HPFRCC mixtures are examined. Also, crack width and development are investigated to determine the effects of the EXAs on the performance of the HPFRCC mixtures, and a performance index is used to quantify the performance of mixture. The results indicate that replacements of 10% CSA-K (Type 1) and 8% CSA-J (Type 2) considerably enhance the mechanical properties and reduce shrinkage of HPFRCCs.
高性能纤维增强水泥基复合材料（HPFRCC）的特点是在非弹性变形过程中出现应变硬化和多裂缝，但它们也会产生高收缩应变。本研究调查了用硫铝酸钙基膨胀剂（CSA EXA）替代波特兰水泥对补偿HPFRCC收缩及相关力学性能的影响。本研究使用了两种化学组成不同的CSA EXA（CSA-K和CSA-J）。对于体积分数为1.5%的聚乙烯（PE）纤维增强的HPFRCC混合物设计，考虑了不同的CSA EXA替代率（按水泥重量计为0%、8%、10%、12%和14%）。对HPFRCC混合物的力学性能，如收缩补偿、抗压强度、抗弯强度和直接抗拉强度进行了研究。此外，还研究了裂缝宽度和扩展情况，以确定膨胀剂对HPFRCC混合物性能的影响，并使用性能指标来量化混合物的性能。结果表明，10%的CSA-K（类型1）和8%的CSA-J（类型2）替代量可显著提高HPFRCC的力学性能并减少其收缩。
