Development of Green and Sustainable Self-Consolidating Engineered Cementitious Composites using Locally Limestone Calcined Clay

Engineered cementitious composites (ECC) are being used to enhance the load-carrying capacity and durability of a structure. However, ECC faces a limitation on dimensional stability and economic and sustainable issues. In general, a large quantity of cementitious materials, often more than 70% by weight, is used in ECC, and no coarse aggregate is allowed to be added. This high amount of Ordinary Portland cement (OPC) dosage not only increases the total cost of ECC but also generates high heat of hydration, increased shrinkage, and low modulus of elasticity compared to its compressive strength. This imposes a negative effect on the mechanical properties of ECC, material cost and material greenness. Replacing cement with supplementary cementitious materials (SCMs), such as fly ash (FA), ground granular blast furnace slag (GGBS), and recycled fine powder (RFP), was demonstrated to be a feasible solution to these problems. However, the ratio of cement to SCM is still high (i.e., 1:1.2 for self-consolidating ECC). Thus, for energy efficiency, low cost, and greening ECC, a large amount of cement can be substituted by limestone calcined clay (LCC) which might also enhance the tensile strength, durability, and shrinkage behaviour of ECC, without a significant reduction in the compressive strength. Moreover, LCC is an environment-friendly material, having high ionic resistivity and a lower CO2 footprint. This will result in high resistance to chloride ingress, low carbon foot print, low shrinkage, low cost, and high ductility. Thus, greenness, durability, and energy efficiency will be attained, which are the cornerstones of sustainability by the use of LCC-ECC. Therefore, this research aims to develop a self-consolidating ECC mix with local limestone and calcined clay to produce a green and sustainable self-consolidating engineered cementitious composite (GSC-ECC).