Physical and chemical effects of El Hadjar slag used as an additive in cement-based materials

Abstract

Granulated blast furnace slag is currently one of the most important sources of materials for the production of blended cements. Since 1999, the use of slag in France has increased by 52% while the increase in clinker production has not exceeded 13%. In times of shortage, the high demand for slag is not always easy to satisfy, and new sources of supply need to be found. The furnace slag of El Hadjar (Annaba, Algeria) comes into this category. The paper deals with the characteristics and reactivity of this slag. A comparison with European slags shows that, although it fulfills all Standards requirements, the El Hadjarslag has slow reaction kinetics. The activity, measured on the compressive strength of mortars whose binder contains 10 to 100% slag of four finenesses ranging from 2500 to 4000 cm 2 /g, strongly depends on the slag fineness. The activity is quantified by using an approach which separates the effect of cement dilution from the physical and chemical effects of the slag.RÉSUMÉ. Les laitiers de hauts fourneaux sont actuellement l'une des plus importantes sources de matériaux pour la production des ciments aux additions. Depuis 1999, l'utilisation des laitiers en France a augmenté de 52 % alors que l'augmentation de la production de clinker n'a pas dépassé 13 %. En période de pénurie, la forte demande en laitier n'est pas toujours facile à satisfaire et de nouvelles sources de matériaux doivent être trouvées. Le laitier d'El Hadjar (Annaba, Algérie) entre dans cette catégorie. Cet article traite des caractéristiques et de la réactivité de ce laitier. Une comparaison avec des laitiers européens montre que, même s'il remplit toutes les exigences normatives, le laitier algérien présente une cinétique de réaction lente. L'activité, mesurée à partir de résistances mécaniques de mortiers contenant entre 10 et 100 % de laitier de quatre finesses entre 2 500 et 4 000 cm 2 /g, dépend fortement de la finesse du laitier. Cette activité est quantifiée en utilisant une approche permettant de séparer l'effet de dilution du ciment des effets physiques et chimiques du laitier.

Effect of Quartz sand Grains Diameter on the Mechanical Properties of Mortars

“…At 28 days; Compressive strength increased by 12%, 10% and 2%, respectively, and mortar blended (30% SD + 70% SC) had a better strength than the other mortars, The crystallized particles of dune sand are involved in the formation of the granular skeleton and contribute to the compactness of the cement matrix, which has been confirmed by the previous studies [5,6]. mortars blended with (30% SD + 70% SC), (50% SD + 50% SC), and (70% SD + 30% SC) increased on the order of 27%, 19%, and 13%, respectively compared to mortar (100% SD) at 3 days, and 44%, 39%, and 30% respectively at 7 eased by 12%, 10% and 2%, respectively, and mortar blended with 30% SD + 70% SC) had a better strength than the The crystallized particles of dune sand are involved in the formation of the granular skeleton of the cement matrix, which has been confirmed by the previous strength for Dds<0.16mm…”

Hydration process of zeolite-rich tuffs and siltstone-blended cement pastes at low W/B ratio, under wet curing condition

“…In order to evaluate the pozzolanic reaction, two main effects were taken into account, such as dilution and carbonation. These two effects played important roles in decreasing the CH content during the hydration (Behim, Cyr, & Clastres, 2011). In this case, for isolating the dilution, the parameters should be expressed over cement content.…”

Efficiency of high energy over conventional milling of granulated blast furnace slag powder to improve mechanical performance of slag cement paste

“…They noticed the reduction of compressive strength with the increase of curing temperature even if they recommend the use of 40°C as a curing temperature for an optimal strength increase trend. Behim and Clastres [33] correlated El Hadjar slag content (0-100%) and finesse (2500-4000 cm 2 /g) to the compressive strength of slag mortars. The largest compressive strengths are related to the largest finesse and smallest content of slag (10%).…”

“…They demonstrate that copper removal is positively correlated to the slag heating temperature. Grinding techniques are also used as mechanical activators [28][29][30][31][32][33]. These techniques increase slag finesse, its specific surface area and thus they are expected to significantly affect pozzolanic and hydration kinetics.…”

“…With classical or conventional grinding slag finesse does not exceed 5000 cm 2 /g after 24 h of milling [32,33]. High energy ball milling allows superior results (up to 9700 cm 2 /g in [29] and 8000 m 2 /g in [30]).…”