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Concrete is a widely used building material due to its strength, durability, and low cost. However, the responsibility of construction sector in climate change encourages the development of low carbon concrete compositions of which the performance and durability in not so well consolidated[1], [2]. The use of hydraulic and pozzolanic by-products allows to reduce the carbon dioxide emissions related to portland clinker production and provides a way to obtain a more sustainable binder for the construction industry but research is needed on the evolution of the physic-chemical properties which constitute the indicators of durability throughout the life the low carbon concrete. To ensure the requirements, it is necessary to use non-destructive testing (NDT) methods for auscultation and evaluation of these structures.
This article discusses the use of electrical resistivity and Young's modulus as non-destructive methods. Electrical resistivity is a measure of the ability of concrete to oppose to electric conduction, and it is related to the porosity and moisture content of material. Young's modulus is a measure of the stiffness of the concrete and can be used to determine the strength and elasticity of the material.
In this paper, we will investigate the role of theses SCM's like slag, fly ash, silica fume, and metakaolin on the variation of these two parameters measured by NDT. The article presents the results of a study that used Wenner electrical resistivity with four electrodes and the dynamic Young's modulus measurements performed on 5 low carbon mixtures of mortar exposed in water cure to assess the microstructure evolution during the hydration phases and pozzolanic reactions and the properties changes with time curing. Different replacement rates of clinker by SCM are used in theses binary compositions, but the water to binder ratio is fixed as well as the total binder quantity and the sand over binder. The optimum percentages of each SCM according to the literature and norms is used in all of our binary compositions.
The results of this study allows us to assess the influence of different binders as replacement of cement on the resistivity measures and the elastic young modulus of mortar at a young age (0 to 2 years) and to be able to understand the changes when analysing the results of other tests that are performed in the PhD thesis.
References:
[1] M. C. G. Juenger and R. Siddique, “Recent advances in understanding the role of supplementary cementitious materials in concrete,” Cement and Concrete Research, vol. 78, pp. 71–80, Dec. 2015, doi: 10.1016/j.cemconres.2015.03.018.
[2] N. De Belie, M. Soutsos, and E. Gruyaert, Eds., Properties of Fresh and Hardened Concrete Containing Supplementary Cementitious Materials: State-of-the-Art Report of the RILEM Technical Committee 238-SCM, Working Group 4, vol. 25. Cham: Springer International Publishing, 2018. doi: 10.1007/978-3-319-70606-1.
