Concrete is the most commonly used material for construction. The worldwide production of cement has greatly increased since 1990.Production of cement results in a lot of environmental pollution as it involves the emission of CO2 gas. Supplementary cementitious materials (SCM) are finely ground solid materials that are used to replace a portion of the cement in a concrete mixture. In order to understand the behaviour of lime-based mortars, and to identify the influence of pozzolonas, it is important to investigate the microstructure and properties of lime-based pastes without any aggregates. In our work nine different sets of pastes with additions of metakaolin and brick dust were studied and compressive strength were investigated . The study revealed that metakaolin exhibits much stronger pozzolonas activity than brick dust, and that the mechanical properties of pastes are not necessarily enhanced by the addition of pozzolona.
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