Study of Mortars Made with Natural and Artificial Pozzolans

The objective of this work is to evaluate the thermal activation potential of clay soils, particularly the clay fraction of dam mud, for the production of artificial pozzolan which can be substituted to cement in concrete and mortars applications and also to make a comparative study with the natural pozzolan available in the area of Beni Saf in considerable quantities. The research study is carried out on three mortars 10, 20 and 30% of natural pozzolan of Beni Saf and artificial pozzolan from the mud calcined at 850 ° C / 3 hours of the dredged sediments of the dams of Fergoug and Ouizert, and on a control mortar without additions for the need of comparison. Several physical, mechanical, microstructural and sustainable tests have been carried out to carry out this research study: maneuverability in the fresh state, impeded shrinkage, mechanical performance, absorption, acid attack (5% CH3COOH, 5% HNO3 and 5% H2SO4), mass loss and pH reading follow-up in the hardened state. Compressive strengths indicate that pozzolan-based mortars have the best results in particular over the long term, whereas the results of acid attack tests show that the calcined mud has a significantly greater influence than natural pozzolan

Prevention of alkali silica reaction risks in mortars by mineral admixtures.

Cette étude expérimentale a pour but de prévenir la réaction alcali-silice (RAS) des mortiers formulés avec des granulats réactifs, où on substitue des taux volumiques de ciment allant de 10% à 50% par des additions minérales telles que le laitier granulé, la pouzzolane naturelle et la fumée de silice. Leur efficacité à contrer les effets néfastes de la RAS, tel que les variations pondérales et dimensionnelles, la largeur et la densité des fissures et les pertes des performances mécaniques ont été étudiés.Les résultats obtenus montrent que le taux et la nature de l'addition influent sur leur efficacité. Pour le laitier granulé et la pouzzolane naturelle le taux idéal est 30%, pour la fumée de silice le taux 10%semble efficace à contrer les effets néfastes de la RAS. Cette efficacité est assurée par la réaction pouzzolanique favorisée par la haute température de l'essai et l'alcalinité du système.The experimental study aims to prevent the alkali-silica reaction (ASR) of mortars made with reactive aggregates, where the volume rates of cement ranging from 10% to 50% are substituted by mineral admixtures such as Granulated Slag, Natural Pozzolan and Silica Fume. Their effectiveness in countering the ASR adverse effects; such as weight and dimensional variations, the width and density of cracks and mechanical performance losses was studied.The results obtained show that the rate and the nature of the mineral admixtures influence their effectiveness, for Granulated Slag and Natural Pozzolan the ideal rate is 30%, for Silica Fume the 10% rate seems effective in countering ASR adverse effects. This effectiveness is ensured by the pozzolanic reaction favored by the high temperature of the test and the alkalinity of the system

Prevention of alkali silica reaction risks in mortars by mineral admixtures.

Cette étude expérimentale a pour but de prévenir la réaction alcali-silice (RAS) des mortiers formulés avec des granulats réactifs, où on substitue des taux volumiques de ciment allant de 10% à 50% par des additions minérales telles que le laitier granulé, la pouzzolane naturelle et la fumée de silice. Leur efficacité à contrer les effets néfastes de la RAS, tel que les variations pondérales et dimensionnelles, la largeur et la densité des fissures et les pertes des performances mécaniques ont été étudiés.Les résultats obtenus montrent que le taux et la nature de l'addition influent sur leur efficacité. Pour le laitier granulé et la pouzzolane naturelle le taux idéal est 30%, pour la fumée de silice le taux 10%semble efficace à contrer les effets néfastes de la RAS. Cette efficacité est assurée par la réaction pouzzolanique favorisée par la haute température de l'essai et l'alcalinité du système.The experimental study aims to prevent the alkali-silica reaction (ASR) of mortars made with reactive aggregates, where the volume rates of cement ranging from 10% to 50% are substituted by mineral admixtures such as Granulated Slag, Natural Pozzolan and Silica Fume. Their effectiveness in countering the ASR adverse effects; such as weight and dimensional variations, the width and density of cracks and mechanical performance losses was studied.The results obtained show that the rate and the nature of the mineral admixtures influence their effectiveness, for Granulated Slag and Natural Pozzolan the ideal rate is 30%, for Silica Fume the 10% rate seems effective in countering ASR adverse effects. This effectiveness is ensured by the pozzolanic reaction favored by the high temperature of the test and the alkalinity of the system

Study of Mortars Made with Natural and Artificial Pozzolans

The objective of this work is to evaluate the thermal activation potential of clay soils, particularly the clay fraction of dam mud, for the production of artificial pozzolan which can be substituted to cement in concrete and mortars applications and also to make a comparative study with the natural pozzolan available in the area of Beni Saf in considerable quantities. The research study is carried out on three mortars 10, 20 and 30% of natural pozzolan of Beni Saf and artificial pozzolan from the mud calcined at 850 ° C / 3 hours of the dredged sediments of the dams of Fergoug and Ouizert, and on a control mortar without additions for the need of comparison. Several physical, mechanical, microstructural and sustainable tests have been carried out to carry out this research study: maneuverability in the fresh state, impeded shrinkage, mechanical performance, absorption, acid attack (5% CH3COOH, 5% HNO3 and 5% H2SO4), mass loss and pH reading follow-up in the hardened state. Compressive strengths indicate that pozzolan-based mortars have the best results in particular over the long term, whereas the results of acid attack tests show that the calcined mud has a significantly greater influence than natural pozzolan

Effect of glass powder and silica fume on mechanical properties and on alkali-silica reaction of recycled glass mortars

In order to value glass in the production of cement and concrete. We have verified the effect of the progressive substitution of 10% to 50% of the volume of cement by glass powder and silica fume on the mechanical properties of hardened mortars, we have also verified their inhibitory effect of the Alkali Silica Reaction (ASR) by studying the variation of mass, expansion, opening and density of cracks as well as the loss of mechanical performance of mortars undergoes a test that accelerates the ASR by autoclave. We have concluded that the use of these mineral admixtures can improve the mechanical performance of mortars, and it can reduce expansions and mechanical performance losses due to ASR

Effect of glass powder and silica fume on mechanical properties and on alkali-silica reaction of recycled glass mortars

In order to value glass in the production of cement and concrete. We have verified the effect of the progressive substitution of 10% to 50% of the volume of cement by glass powder and silica fume on the mechanical properties of hardened mortars, we have also verified their inhibitory effect of the Alkali Silica Reaction (ASR) by studying the variation of mass, expansion, opening and density of cracks as well as the loss of mechanical performance of mortars undergoes a test that accelerates the ASR by autoclave. We have concluded that the use of these mineral admixtures can improve the mechanical performance of mortars, and it can reduce expansions and mechanical performance losses due to ASR

Mechanical behaviour of Composites based on Diss and Aflfa fibres in different matrices

The use of natural fibers in cementitious matrices has an incompatibility, which results considerable retardation of setting and very low resistances during the composite tests with natural crushed Diss, despite the fact that the fibers have considerable tensile strengths, because of the sugars and water- soluble components contained in natural plants. To improve the fibers contribution in cementitious composites, we have carried out a treatment by boiling the natural fibers to extract the substances responsible for the bad connection between fibers and the cement paste. This phenomenon of incompatibility disappears with the use of clay matrix or lime, which allows using the fibers without any treatment. We were able to determine the mechanical behavior of composites in flexion and compression by measuring stresses and deformations. Through our vast experimental program on the composites of natural fibers of Alfa and Diss in different matrices (cement and clay) and different sizes ranging from 2 to 8 cm, we have found: 1) The best resistance in bending and compression are generally reached for the composites with fibers having the dimensions between 4 and 6 cm. 2) The best bending strengths are achieved for composites with cementitious matrices, because of the good adhesion of the fibers to the matrix. 3) The best compressive strengths are achieved for clay matrix composites, which are due to the good compressibility of the clay. 4) The composites of Alfa and Diss fibers presented a very ductile behavior as well in flexion as in compression, contrary to the pure binder paste which has a brittle behavior. 5) The composites obtained have a very low density, which makes it possible to classify them as lightweight materials and have a very ductile behavior, which suggests using these materials as filling in the seismic zones

Mechanical behaviour of Composites based on Diss and Aflfa fibres in different matrices

The use of natural fibers in cementitious matrices has an incompatibility, which results considerable retardation of setting and very low resistances during the composite tests with natural crushed Diss, despite the fact that the fibers have considerable tensile strengths, because of the sugars and water- soluble components contained in natural plants. To improve the fibers contribution in cementitious composites, we have carried out a treatment by boiling the natural fibers to extract the substances responsible for the bad connection between fibers and the cement paste. This phenomenon of incompatibility disappears with the use of clay matrix or lime, which allows using the fibers without any treatment. We were able to determine the mechanical behavior of composites in flexion and compression by measuring stresses and deformations. Through our vast experimental program on the composites of natural fibers of Alfa and Diss in different matrices (cement and clay) and different sizes ranging from 2 to 8 cm, we have found: 1) The best resistance in bending and compression are generally reached for the composites with fibers having the dimensions between 4 and 6 cm. 2) The best bending strengths are achieved for composites with cementitious matrices, because of the good adhesion of the fibers to the matrix. 3) The best compressive strengths are achieved for clay matrix composites, which are due to the good compressibility of the clay. 4) The composites of Alfa and Diss fibers presented a very ductile behavior as well in flexion as in compression, contrary to the pure binder paste which has a brittle behavior. 5) The composites obtained have a very low density, which makes it possible to classify them as lightweight materials and have a very ductile behavior, which suggests using these materials as filling in the seismic zones