Abstract This work examines the impact of mordenite-rich tuff (MT) on the technological properties of fired clay brick. These specimens were obtained by substituting clay with MT in various proportions (0, 5, 10, 15, 20, 50, and 100 wt%). They were pressed at 10 MPa, air-dried in the laboratory, and fired at 900 °C using two different clays: clay of Remila (CR) and clay of Adjiba (CA), Algeria. The mechanical, thermal, and physical properties of fired bricks were determined and compared to those of control bricks (0 wt%). According to the finding, the partial and total substitution of clay by MT reduced the sample’s thermal conductivity and bulk density. Thus, the MT increased the apparent porosity and the water absorption of clay brick while maintaining the compressive strength within the limits of the Algerian standards. This research revealed the possibility of producing bricks containing up to 100% by weight of MT with the required technical and environmental properties.

Abstract The advantages of using zeolites are lower costs and better durability, but it requires longer setting time and slower strength development. Chemical and thermal methods have been developed to overcome these disadvantages and to enhance the reactivity of natural zeolite. This paper addressed through a parametric experimental pozzolanic reactivity, the strength and setting time by varying the cure temperature and the amount and type of chemical activators. To this end, several mixtures of natural zeolite-lime pastes were made with two concentrations of chemical activators including 4% and 8% of NaOH, NaCl, and CaSO4.2H2O. The produced pastes were cured at 20, 40, and 80 °C. The blends were also analyzed by X-ray diffraction and infrared spectroscopy. The results showed that curing at high temperatures accelerated the pozzolanic reactivity and increased the compressive strength. The use of CaSO4.2H2O led to an increase in the consumption of Ca(OH)2 and strength. Adding NaCl improved slightly the compressive strength at high curing temperatures. The addition of 8% NaOH at 40 °C significantly improved reactivity and strength. Setting time was accelerated by adding chemical activators to the blends. The raw zeolite had good pozzolanic activity, but the addition of CaSO4.2H2O enhanced it.

Resumo O objetivo deste estudo foi examinar a utilização de argila calcinada (CC), que é um material pozolânico, em substituição a 10% em massa da quantidade de cimento, para a estabilização/solidificação (S/S) de resíduos perigosos usando um ligante hidráulico. Para comparação, foi usado um cimento Portland comum. O teste padrão de procedimento de lixiviação de característica de toxicidade (TCLP) mostrou que as concentrações médias de metais pesados no resíduo perigoso excederam em muito as dos padrões exigidos. A lixiviação dos metais pesados da argamassa foi avaliada pelo teste de lixiviação de monolito (MLT) sob condições de lixiviação dinâmica por 64 dias em meio sulfatado e neutro. Testes de resistência à compressão, tempos de pega e difração de raios X foram realizados. A adição de CC melhorou consideravelmente a resistência das amostras de argamassa contendo resíduo perigoso. De acordo com o ensaio MLT, a argamassa com CC cimentícia foi mais eficiente no S/S de metais pesados do que a argamassa feita sem CC.

Abstract The aim of this study was to examine the use of calcined clay (CC), which is a pozzolanic material, as a substitute for 10% by weight of the amount of cement, for the stabilization/solidification (S/S) of hazardous waste using a hydraulic binder. For comparison, an ordinary Portland cement was used. The standard toxicity characteristic leaching procedure (TCLP) test showed that the average concentrations of heavy metals in the raw hazardous waste far exceeded those of the required standards. Leaching of heavy metals from the mortar was evaluated by the monolithic leaching test (MLT) under dynamic leaching conditions for 64 days in sulfated and neutral media. Tests of compressive strength, setting times, and X-ray diffraction were carried out. The addition of CC considerably improved the strength of the mortar specimens containing hazardous waste. Following the MLT test, CC cement-made mortar was more efficient in the S/S of heavy metals than mortar made without CC.

Resumo O principal objetivo do presente estudo consistiu em analisar o efeito do diâmetro de caroços de tâmara moídos (CTM) nas propriedades tecnológicas de um tijolo de argila. Para esse propósito, foram misturadas quantidades crescentes de CTM (0, 5, 10, 15 e 20 wt%) com diferentes diâmetros a uma argila para produzir tijolos cerâmicos por prensagem, secagem e queima a 900 ºC. O diâmetro e a fração de CTM alteraram o teor de água necessário para plasticidade. A retração, a absorção de água e a porosidade dos tijolos após queima aumentaram com a fração e o diâmetro do CTM. A resistência à compressão, a densidade aparente e a condutividade térmica das amostras diminuíram com o aumento do diâmetro e da fração de CTM. A partir de micrografias de MEV, foi observado que a combustão do CTM adicionado causou a redução do diâmetro dos poros formados nas amostras de tijolo queimado.

Abstract The main aim of this study was to evaluate the effect of diameter of ground date pits (GDP) on the technological properties of a clay brick. For this purpose, increasing amounts of GDP (0, 5, 10, 15 and 20 wt%) with different diameters were mixed with a clay to produce clay bricks by pressing, drying and then firing at 900 °C. The GDP diameter and content changed the water requirement for plasticity. The shrinkage, water absorption and apparent porosity of fired clay brick increased with the content and diameter of GDP. The compressive strength, apparent density and thermal conductivity of the samples decreased with the increase in diameter and content of GDP. With the help of SEM micrographs, it was observed that the combustion of added GDP in the mixture led to a reduction in the diameter of pores formed in the fired clay brick samples.