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This paper evaluates the hydration of oil well cement pastes containing sodium chloride (NaCl) and potassium chloride (KCl) using thermal analysis. Pastes were designed containing up to 36 % of NaCl and up to 34 % of KCl by the mass of water and water to cement ratio of 0.44. The curing was performed at 60°C up to 7 days. X-ray diffraction was used with a complementary technique to identify the products formed. The results show that the pastes with salt addition presented the formation of Friedel's salt due to the interaction of the ion Cl -with the aluminate phases. The dehydroxylation temperature of calcium hydroxide lowered with the increment of percentage of salt addition. At the first hours of curing, NaCl and KCl have accelerated the hydration reactions. For later ages, NaCl addition has retarded the hydration reactions and KCl has not modified significantly this property. Exceptions from these were observed for saturated pastes (36 % NaCl and 34 % KCl) that had the hydration reactions retarded in all ages evaluated.

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The present work aims to study the replacement of Portland cement (PC) by stone cutting waste (SW) and ground waste clay brick (BW) in binary and ternary pastes. Thermogravimetry and differential thermal analysis tests were carried out at various ages in order to investigate the development of the cement hydration reactions in the presence of those wastes. The packing density was calculated in accordance with the Compressible Packing Model to understand the physical effect of those wastes. Compressive strength tests were also performed and the results were related to hydration and packing. Considering the substitution levels studied, the results indicated that the use of SW in the binary mixture accelerated the hydration reactions, and the particles packing density and compressive strength were maintained. The use of BW in the binary mixture caused a small acceleration in the hydration reactions and there was an indication of pozzolanic activity, although the compressive strength was reduced in comparison with the reference paste. In the ternary mixture, the combined effect of both wastes resulted in the maintenance of compressive strength for cement replacement content of 30%.Keywords: stone cutting waste, ground waste clay brick, cementitious pastes, thermal analysis, packing density, compressive strength.O presente trabalho teve por objetivo estudar a substituição do cimento Portland (CP) por resíduos de corte de rochas (RCR) e de blocos cerâmicos moídos (RBC) em pastas binárias e ternárias. Ensaios de termogravimetria e de análise térmica diferencial foram realizados em várias idades com a finalidade de investigar a evolução das reações de hidratação de cimento em presença dos resíduos. Para compreender o efeito físico dos resíduos foi calculada a densidade de empacotamento de acordo com o Modelo de Empacotamento Compressível. Ensaios de resistência à compressão também foram realizados e os resultados foram relacionados com a hidratação e o empacotamento. Considerando os níveis de substituição estudados, os resultados indicaram que a utilização do RCR na mistura binária acelerou as reações de hidratação, e a densidade empacotamento das partículas e a resistência à compressão foram mantidas. A utilização do RBC na mistura binária provocou uma pequena aceleração nas reações de hidratação e houve indícios de atividade pozolânica, embora a resistência à compressão tenha reduzido em comparação com a referência. Na mistura ternária, o efeito conjunto de ambos os resíduos acarretou a manutenção da resistência à compressão para um teor de substituição de cimento de 30%.Palavras-chave: resíduo de corte de rochas, resíduo de blocos cerâmicos, pastas cimentícias, análise térmica, densidade de empacotamento, resistência à compressão. Influence of stone cutting waste and ground waste clay brick on the hydration and packing density of cement pastes Influência de resíduos de corte de rochas e de blocos cerâmicos moídos na hidratação e no empacotamento de pastas cimentíciasAbstract Resumo

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