Dimensional stability of engineered cementitious composites

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2012
Keskin, Süleyman Bahadır
Cementitious materials with strain-hardening property and high tensile ductility are promising materials on account of their mechanical and durability performances. These materials require special ingredients which make it costly to be used in conventional constructions. Hence, potential applications of Engineered Cementitious Composites (ECC) generally focus on layered systems or repairs which require the use of ECC together with another material. For it to be used especially as a repair material, it should have sufficient dimensional compatibility for preventing restrained shrinkage cracking. In this thesis, a strain-hardening fiberreinforced cementitious composite, named Engineered Cementitious Composites, was produced with local ingredients and their mechanical performance, dimensional stability properties were investigated. For investigating the effect of materials and mix proportions on mechanical properties, compressive strength, flexural strength with mid-span beam deflections and matrix fracture toughness tests were conducted. For determining the dimensional compatibility properties, autogenous, drying and restrained shrinkage tests were conducted along with tensile creep tests. As a result it was shown that, mechanical and dimensional stability properties are affected by the ingredients and mix proportions. It was shown that especially autogenous shrinkage of mixtures was relatively high which can cause early age cracking. In order to mitigate the adverse effect of autogenous shrinkage, the effect of pre-soaked expanded perlite aggregate replacement on mechanical, shrinkage and dimensional compatibility properties was investigated. As a result it was found out that autogenous shrinkage can be mitigated by the use of pre-soaked expanded perlite aggregate replacement.