Study the use of Nano-limestone and Egg-shell Ash in Eco-friendly SCC: an Experimental and Statistical Evaluation Based on Computer Programming

The main concrete effect on the environment is the CO2 emissions during cement production. Calcium carbonate is the major component of both egg-shell and limestone; also, it is the primary raw material in the production of cement. Although there is researches on egg-shell powder (ESP) and nano-limestone powder (NLP) separately, there is a non to limited on both powders in production self-consolidating concrete (SCC). This paper reports a feasibility study of producing SCC with a lower impact on the environment by incorporating and egg-shell powder as partial replacement of cement. Different SCC mixtures were designed at a consistent water-to-binder ratio and a binder content of 0.34 and 450 kg/m3, respectively. The cement was partially replaced with an equal amount of limestone and egg-shell powder at percentages of 10, 15, 20, and 30 % by weight of cement. Both rheological and hardened properties for the resulting concrete were studied. Also, the durability of the proposed mixture was tested in terms of residual compressive strength and density after exposure to high temperatures. The results showed that the rheological properties of all developed mixtures are met the requirements recommended by the European Federation of National Associations Representing for Concrete (EFNARC) for SCC. While the hardened properties are structurally acceptable. On the other hand, higher residual strength and less reduction were achieved compared to the control mixture under high temperatures. Finally, the computer analysis of the derived statistical compressive strength models can be effectively used to predict the compressive strength of SCC.