Jardel Pereira Gonçalves

Utilização do resíduo da indústria cerâmica para produção de concretos

This paper presents the results of a study on the use of ground calcined-clay brick residuals, produced by the ceramic industry, as a supplementary pozzuolanic cementing material for use in concrete. The ceramic residue was characterized by physical, chemical and mineralogical tests. The feasibility of the substitution of the cement by the ceramic residue was evaluated by performing mechanical tests on the concrete samples. The properties investiged were stress-strain behavior, compressive strength, flexural strength and splitting tensile strength. The results pointed out that there is a potential for the use of ceramic residue as a supplementary cementing material in concrete production. Concretes containing ceramic residue (20% of cement replacement by weight) presented equal strength and lower elastic modulus than the control mixes.

Evaluation of the Metakaolin Pozzolanic Reactivity in Cement Pastes

The pozzolanic reactivity of a commercial metakaolin (MK) manufactured in Brazil, was evaluated in pastes prepared with a type II Portland cement, when used in cement substitution degrees from 10 to 40 mass % by thermal analysis techniques. The reactivity during the early stages of hydration was studied in real time from Non-Conventional Differential Thermal Analysis curves, normalized by the effect of the specific heats of the raw materials. The total pozzolanic reactivity after 28 days of hydration was evaluated by the calcium hydroxide consumption, calculated from thermogravimetric and derivative thermogravimetric curves of the pastes, obtained on cement oxide calcined basis. This also allows one to a more accurate determination of the uncombined and total combined water in the pastes than usual procedures. The MK pozzolanic reactivity during the early stages and after a month is proportional to the cement substitution degree in the pastes.