Engineered cementitious composites with low volume of cementitious materials

Abstract

Engineered cementitious composite (ECC) is an ultra ductile cement-based material reinforced with fibers. It is characterized by high tensile ductility and tight crack width control. Thanks to the excellent performance, ECC is emerging in broad applications to enhance the loading capacity and the durability of structures. However, ECC also faces a limitation on dimensional stability and on economical and sustainable issues. In general, a large amount of cementitious materials, often more than 70% by weight, is used in ECC and no coarse aggregate is allowed to be added. The high volume of cementitious materials in ECC results in a large drying shrinkage and negative effects on material cost and material greenness. In this paper, a new version of ECC is designed with low volume of cementitious materials about 25% by weight, including Portland cement, blast furnace slag and silica fume, and a large amount of filler and aggregate, including limestone powder and river sand. In this mix, only 1.2% of fibers by volume is mixed, which is 60% dosage of standard ECC. Experimental study reveals that the newly developed ECC shows tensile ductility of 2% and relatively low shrinkage. Considering the low cementitious material and fiber contents, the newly developed ECC might have a reduced cost and increased material greenness.