Percorrer por autor "Merelles, Samira"
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- Diatomaceous earth as a partial replacement for portland cement in mortars - a reviewPublication . Magalhães, Leandro; Gavilán, Ana; Ferreira, Débora; Merelles, SamiraOver the last years, the increase in CO2 emissions into the atmosphere, its impact on climate change, and issues related to the sustainability and environmental impacts generated by the participation of the construction industry in global warming, have led to countless researches, several of them looking to modernize cement production with alternative binders. The most known alternative binders used nowadays in the construction industry are slag obtained in blast furnaces, metakaolin and fly ashes obtained from burning coal in thermoelectric power stations. In the present paper, due to diatomaceous earth’s pozzolanic properties, is researched the possibility of the use of diatomaceous earth as an alternative binder. This work shows a review of studies about introduction of raw and calcined diatomaceous earth in cement mortars, and the feasibility of using this material as a binder in cement mortars. The different studies present that the introduction of different percentages of diatomaceous earth in mortars influences the physical and mechanical characteristics of the manufactured mortars. The tests performed in mortars with introduction of calcined diatomaceous earth show that the mechanical strength improves when compared to mortars manufactured with raw diatomaceous earth. The results of the compressive and flexural strength in mortars with introduction of calcined diatomaceous earth present lower values during the first 28 days, when compared with mortars without diatomaceous earth, however, there is a significant increase in the values of mechanical resistance, surpassing the values of mechanical resistance of mortars without diatomaceous earth at the end of 90 days. The water absorption by immersion tests also reveal that the increased introduction of diatomaceous earth increases the water absorption of the mortars.
- Diatomaceous earth as a partial replacement for portland cement in mortars - a reviewPublication . Magalhães, Leandro; Merelles, Samira; Ramos Gavilán, Ana; Ferreira, DéboraOver the last years, the increase in CO2 emissions into the atmosphere, its impact in climate change, and issues related to the sustainability and environmental impacts generated by the participation of construction industry in the global warming, which is responsible for about 8% of world CO2 emissions, have led to countless research, several of them looking for modernize cement production with alternative binders. In the present paper, it is researched the possibility of the use of diatomaceous earth as an alternative binder. The most known alternative binders used nowadays in construction industry are slag, metakaolin and fly ashes. These materials are known for its pozzolanic properties, and when used in cement mixtures, they can improve the concrete and mortars mechanical characteristics. Focus of this paper, and very similar to metakaolin and fly ash, there is the residual diatomaceous earth, a material with high porosity and low thermal conductivity, with pozzolanic properties and another waste product that can be used in the construction sector. Following the concept of sustainable construction, this work shows an extensive review of studies about introduction of residual diatomaceous earth in cement mortars, and the feasibility of using this material as a binder in cement mortars. Also, this paper brings details of some physical and mechanical properties of mortars made with diatomaceous earth, such as compression and flexural strength, and water absorption; and some features of residual diatomaceous earth like mineralogical analysis, chemical analysis, bulk density and particles size.