Use of metakaolin or coal gangue as a partial substitution of cement in mechanical performance of PC mortars

Abstract

This work investigates the feasibility of the use of high temperature pozzolan such as metakaolin (Mk) and other industrial waste, such as coal gangue without burned, mortars were made with the aim of improving, through various dosages, their physical and mechanical properties and durability. Mortars were subjected to destructive tests as well as non-destructive tests in hardened state: electrical resistivity (ER), with trial ages of 14, 28, 45, 90, 180 and 360 days. The percentages of the substitutions were 5, 10, 15, 20 and 30% with respect to the weight of Portland cement and a control mixture (cement–sand–water) was produced as a reference parameter. A comparative study was carried out with the results of the aforementioned tests, to estimate the quality and porosity of each mixture. It is observed that the tests of ER indicate indirectly the porosity of the material, the mixtures elaborated with Mk improved the mechanical properties with respect to the control mixture. With the partial replacement of the cement and according to the tests carried out, it can be observed that the problem of durability and CO₂ emissions to the atmosphere is reduced significantly diminishing the attack on our planet.

Keywords:

• Cement mortar
• metakaolin
• coal gangue
• pozzolan