The effect of cement substitution by two mineral admixture on the sustainability of concrete at curing temperature

摘要

Nowadays, concrete has become the most consumed material ever used, it is a heterogeneous and composite material, where the name heterogeneity refers to the large difference between its compressive and tensile behavior, and the name composite refers to the constitution of concrete. Generally, concrete is composed of cement, the binding element, and the aggregate that represents the granular structure. Actually, more components are injected in the concrete composition like mineral and chemical admixtures. The principal purpose of the introduction of more mineral admixture is to minimize costs and make a sustainable concrete, principally if this addition is originally a waste. Actually, in the field of construction, the transport of aggregate represents 14% of CO_2 emissions; for this reason the current tendency is to make concrete based on abundant local material. The main reason of using SCM (sustainable concrete material) is material reliability; the SCM used in our study is a waste resulting from crushed aggregate manufactory composed principally by 40% limestone (seize less than 80µm). On the other hand, the cement manufactory is responsible by 24% of CO_2 emissions. The main aspect of this study is the use of SCM limestone as substitution of cement, to minimize the quantity of the cement used in the composition of concrete; the principal objective is environmental and economic. Concrete is a receptive material, which means that it may be influenced by its environment; in this context we studied the effect of curing temperature of the environment on the mechanical characteristics of concrete based on the substitution of cement with two mineral admixtures.