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Gretta Shapiro - One of the best experts on this subject based on the ideXlab platform.
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Properties of cement Mortar incorporating de-inking waste-water from waste paper recycling
Construction and Building Materials, 2012Co-Authors: Kwesi Sagoe-crentsil, Gretta ShapiroAbstract:Abstract This paper presents results of an investigation into the potential use of recycling paper mill waste-water to replace mixing water in cement Mortar systems for manufacturing concrete masonry products. The physical and mechanical properties of Mortar containing various amounts of de-inking waste-water were consequently investigated. A key finding of this study was that replacing Mortar mixing water with waste-water significantly improved workability and consistency of cement Mortar mixtures. In particular the flow of Mortar mixtures increased with increase of waste-water content up to 50% and then levelled off when waste-water content exceeded 50%. Correspondingly, the flow of Mortar mix with 100% waste-water replacement at water/cement ratio of 0.50 was found to be equivalent to that of the Reference Mortar mix with 100% potable water at water/cement ratio of 0.60, indicating potential use of de-inking waste-water as water reducing admixture. The enhanced workability arising from waste-water addition however induced changes in mechanical properties of the hardened material. Compared to Reference Mortar, replacing 10% and 100% potable water respectively resulted in 19% and 60% reduction of compressive strength, with a corresponding 5% and 16% drop in bulk density, and up to 19% increase in drying shrinkage. Also, water absorption and volume of permeable voids increased with increasing waste-water dosage, albeit marginally. The benefits derived from rheology improvements compared to compromises in mechanical properties due to de-inking waste-water addition strongly indicate clear potential of using de-inking waste-water in production of lightweight cementitious building and masonry elements.
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Reuse of de-inking sludge from wastepaper recycling in cement Mortar products.
Journal of Environmental Management, 2011Co-Authors: Kwesi Sagoe-crentsil, Gretta ShapiroAbstract:This paper presents results of an investigation into the use of de-inking sludge from a paper recycling mill as feedstock material in the manufacture of cement Mortar products, including masonry blocks and Mortar renders. Both physical and mechanical properties of Mortar specimens containing various amounts of de-inking sludge were investigated. It was observed that the addition of de-inking sludge to cement Mortar at a fixed water-to-cement ratio significantly reduced flow properties and increased setting time. Water absorption and volume of permeable voids of cement Mortar increased with increased dosage of de-inking sludge, with a corresponding reduction of bulk density. The 91-day compressive strength of Mortar samples with 2.5 wt% and 20 wt% de-inking sludge loadings retained 83% and 62% respectively of the Reference Mortar strength. The corresponding drying shrinkage increased by up to 160% compared to Reference samples. However, a de-inking sludge loading of up to 2.5 wt% did not significantly alter measured physical and mechanical properties. The results demonstrate that despite the high moisture absorbance of de-inking sludge due to its organic matter and residual cellulose fibre content, it serves as a potential supplementary additive and its cellulosic content proving to be an active set retardant to cementitious masonry products.
Kiang Hwee Tan - One of the best experts on this subject based on the ideXlab platform.
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use of waste glass as sand in Mortar part i fresh mechanical and durability properties
Cement & Concrete Composites, 2013Co-Authors: Kiang Hwee TanAbstract:In this study, Mortar made with waste glass as fine aggregates was investigated for its suitability for construction use. A Reference Mortar mixture was proportioned according to ASTM C 109 and the fine aggregates were replaced by waste glass particles by 0%, 25%, 50%, 75% and 100%, by mass, to study its effect on the properties of Mortar. For each mixture, four types of glass sand, namely, brown, green, clear and mixed color glass, were used. Test results indicated that use of waste glass particles as fine aggregates would reduce the flowability and density of Mortar, but increase its air content. Except drying shrinkage, the mechanical properties were compromised due to micro-cracking in glass sand and weakened bond with the cement paste. However, durability was enhanced, especially in terms of the resistance to chloride ion penetration. Accelerated Mortar bar tests to ASTM C 1260 indicated that green and brown glasses were non-reactive while clear glass was potentially deleterious, with regards to alkali–silica reaction.
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Use of waste glass as sand in Mortar: Part I – Fresh, mechanical and durability properties
Cement and Concrete Composites, 2013Co-Authors: Kiang Hwee TanAbstract:In this study, Mortar made with waste glass as fine aggregates was investigated for its suitability for construction use. A Reference Mortar mixture was proportioned according to ASTM C 109 and the fine aggregates were replaced by waste glass particles by 0%, 25%, 50%, 75% and 100%, by mass, to study its effect on the properties of Mortar. For each mixture, four types of glass sand, namely, brown, green, clear and mixed color glass, were used. Test results indicated that use of waste glass particles as fine aggregates would reduce the flowability and density of Mortar, but increase its air content. Except drying shrinkage, the mechanical properties were compromised due to micro-cracking in glass sand and weakened bond with the cement paste. However, durability was enhanced, especially in terms of the resistance to chloride ion penetration. Accelerated Mortar bar tests to ASTM C 1260 indicated that green and brown glasses were non-reactive while clear glass was potentially deleterious, with regards to alkali–silica reaction.
Kwesi Sagoe-crentsil - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of fly ash geopolymer Mortar incorporating calcined wastepaper sludge
Journal of Sustainable Cement-Based Materials, 2016Co-Authors: Shiqin Yan, Kwesi Sagoe-crentsilAbstract:This study evaluates fresh and hardened properties of fly ash geopolymer Mortars incorporating calcined wastepaper sludge cured under ambient conditions. The calcined sludge geopolymer mixtures were characterized by XRD, XRF, and SEM–EDS techniques. It was observed that addition of up to 40 wt% calcined sludge in geopolymer Mortars at a fixed liquid/solid mass ratio of 0.2 reduced flow of Mortars from 112 to 61%, while the corresponding setting time was shortened from 113 h to just under 1 h. At the maximum calcined sludge loading of 40 wt%, the compressive strength at 7 days was 29.0 MPa, a significant increase from 3.8 MPa for Reference Mortar samples with no addition of sludge. Correspondingly, a nearly fourfold reduction in 56-day drying shrinkage measured at 3600 microstrains was observed, compared to Reference Mortars. The plausible reaction mechanisms, in particular, apparent concurrent formation of C-A-S-H/N-(C)-A-S-H phases alongside geopolymer gel networks are discussed in detail.
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Properties of cement Mortar incorporating de-inking waste-water from waste paper recycling
Construction and Building Materials, 2012Co-Authors: Kwesi Sagoe-crentsil, Gretta ShapiroAbstract:Abstract This paper presents results of an investigation into the potential use of recycling paper mill waste-water to replace mixing water in cement Mortar systems for manufacturing concrete masonry products. The physical and mechanical properties of Mortar containing various amounts of de-inking waste-water were consequently investigated. A key finding of this study was that replacing Mortar mixing water with waste-water significantly improved workability and consistency of cement Mortar mixtures. In particular the flow of Mortar mixtures increased with increase of waste-water content up to 50% and then levelled off when waste-water content exceeded 50%. Correspondingly, the flow of Mortar mix with 100% waste-water replacement at water/cement ratio of 0.50 was found to be equivalent to that of the Reference Mortar mix with 100% potable water at water/cement ratio of 0.60, indicating potential use of de-inking waste-water as water reducing admixture. The enhanced workability arising from waste-water addition however induced changes in mechanical properties of the hardened material. Compared to Reference Mortar, replacing 10% and 100% potable water respectively resulted in 19% and 60% reduction of compressive strength, with a corresponding 5% and 16% drop in bulk density, and up to 19% increase in drying shrinkage. Also, water absorption and volume of permeable voids increased with increasing waste-water dosage, albeit marginally. The benefits derived from rheology improvements compared to compromises in mechanical properties due to de-inking waste-water addition strongly indicate clear potential of using de-inking waste-water in production of lightweight cementitious building and masonry elements.
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Reuse of de-inking sludge from wastepaper recycling in cement Mortar products.
Journal of Environmental Management, 2011Co-Authors: Kwesi Sagoe-crentsil, Gretta ShapiroAbstract:This paper presents results of an investigation into the use of de-inking sludge from a paper recycling mill as feedstock material in the manufacture of cement Mortar products, including masonry blocks and Mortar renders. Both physical and mechanical properties of Mortar specimens containing various amounts of de-inking sludge were investigated. It was observed that the addition of de-inking sludge to cement Mortar at a fixed water-to-cement ratio significantly reduced flow properties and increased setting time. Water absorption and volume of permeable voids of cement Mortar increased with increased dosage of de-inking sludge, with a corresponding reduction of bulk density. The 91-day compressive strength of Mortar samples with 2.5 wt% and 20 wt% de-inking sludge loadings retained 83% and 62% respectively of the Reference Mortar strength. The corresponding drying shrinkage increased by up to 160% compared to Reference samples. However, a de-inking sludge loading of up to 2.5 wt% did not significantly alter measured physical and mechanical properties. The results demonstrate that despite the high moisture absorbance of de-inking sludge due to its organic matter and residual cellulose fibre content, it serves as a potential supplementary additive and its cellulosic content proving to be an active set retardant to cementitious masonry products.
Rosário Veiga - One of the best experts on this subject based on the ideXlab platform.
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Rendering Mortars with Low Sand and Cement Content. Incorporation of Sanitary Ware Waste and Forest Biomass Ashes
Applied Sciences, 2020Co-Authors: Catarina Brazão Farinha, Jorge De Brito, Rosário VeigaAbstract:The incorporation of wastes in new materials and products is an emerging trend, reducing virgin materials’ consumption and landfill deposition and the associated environmental impacts. Cement-based Mortars can encapsulate some wastes, with the benefits stated above. In three previous researches, it was found that forest biomass bottom ashes (up to 15% by volume of cement), powder of sanitary ware (up to 20% by volume of sand) and sanitary ware particles above 2 mm (100% by volume of sand) can be incorporated in rendering Mortars, replacing cement or sand. Several tests were performed, and it was found that each waste’s incorporation presents advantages and limitations, when compared with a Reference Mortar. In this research, the aim was to take advantage of the best features of each waste, combining them in order to optimize the new Mortars’ characteristics. Therefore, Mortars with one, two and three wastes were analysed in this research. The ternary mix Mortar had a volume of wastes equal to 83%, resulting in a Mortar with 15% less cement (by volume) and without any natural aggregate (all replaced with the sanitary ware wastes). The fresh, water and mechanical behaviour of the Mortars with and without wastes are presented in this research. It was concluded that it is possible to take advantage of the best features of each waste and achieve Mortars simultaneously with high volume of wastes and a better performance than the Reference Mortar (without wastes).
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Reduction of cement content in renderings with fine sanitary ware aggregates
Materials and Structures, 2016Co-Authors: C. Farinha, Rosário Veiga, J. LucasAbstract:The aim of this research is to present a viable solution for the reduction of cement content in Mortars, by recycling a non-biodegradable material, such as grinded sanitary ware fines. This research analysed the reduction of cement content from a volumetric ratio of 1:4 (cement: aggregates) to 1:5 and 1:6 with simultaneous incorporation of fines from sanitary ware waste (SWW). The fines incorporated were below 149 μm and were incorporated as 20 % of the aggregates volume. Several tests were carried out in the fresh and hardened states, namely water retention, flexural and compressive strengths, water absorption by capillarity, permeability to water under pressure and to water vapour and dimensional instability. It was found that the reduction of cement content and incorporation of SWW allowed better performance on most of the tests than that of the Reference Mortar (1:4 ratio).
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Incorporation of fine sanitary ware aggregates in coating Mortars
Construction and Building Materials, 2015Co-Authors: Catarina Brazão Farinha, J. De Brito, Rosário VeigaAbstract:Abstract This paper analyses the behaviour of cement Mortars with addition of grinded fine sanitary ware (GSWF) aggregates, in percentages of 0%, 10%, 15% and 20% of the natural aggregates’ volume, to be used as renderings. The effect of these recycled materials was studied in an experimental programme through several tests. The performance of these modified Mortars was evaluated in terms of strength, water absorption, water retention, dimensional instability and water permeability. Some extra tests were also formulated to understand the microstructure of these Mortars such as open porosity and magnifying glass observation. The research results were very positive since the modified Mortars had, in the most tests, better performance than the Reference Mortar (0% of GSWF addition). The modified Mortar with 20% addition of GSWF was the one with the best performance of all the modified Mortars, in particular in terms of higher strength and lower water absorption.
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Reduction of the cement content in Mortars made with fine concrete aggregates
Materials and Structures, 2014Co-Authors: Mariana Braga, Rosário VeigaAbstract:This study’s main objective is to show the viability of reducing the cement content of Mortars by incorporating fine crushed concrete aggregates whilst simultaneously maintaining a good performance in terms of functional requisites. The advantages of this, if the results are positive, are both environmental and economic: less energy is consumed in cement manufacture and the Mortars’ direct costs are lower. To evaluate the hypothetical binding characteristics of concrete fines incorporated in Mortars, and thus allow a cement consumption reduction, various standard tests were performed to quantify their most important properties (e.g. mechanical strength, water-related performance, cracking susceptibility, shrinkage) and compare them with those of a Reference Mortar containing no recycled fines and not reducing the cement content.
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using fine recycled concrete aggregate for Mortar production
Materials Research-ibero-american Journal of Materials, 2013Co-Authors: Catarina Neno, Jorge De Brito, Rosário VeigaAbstract:This research assessed the performance of Mortars in which recycled concrete aggregates (RCA) was a component. It replaced natural sand but kept the same particle size distribution. Three Mortars were produced with replacement ratios of 20%, 50% and 100% as well as a Reference Mortar containing no recycled aggregate. The compressive and flexural strength, water absorption by capillarity, drying capacity and susceptibility to cracking of these Mortars were analyzed first. Then, based on these results, the most satisfactory replacement ratio was chosen and the following properties were analyzed: water retentivity, shrinkage, adhesive strength, modulus of elasticity, and water vapor permeability. Somewhat surprisingly the best results in the first stage occurred for 20% and 100% replacement ratios, leading to a cautious choice of the 20% ratio for the second stage. Generally the Mortar with 20% replacement ratio performed better than the Reference Mortar, except for adhesive strength and dimensional stability.
Ronaldo A. Medeiros-junior - One of the best experts on this subject based on the ideXlab platform.
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Effect of improved autogenous Mortar self-healing in the alkali-aggregate reaction
Cement and Concrete Composites, 2021Co-Authors: Guilherme Da Silva Munhoz, Mateus Edilson Gomes Dobrovolski, Eduardo Pereira, Ronaldo A. Medeiros-juniorAbstract:Abstract This article evaluated the effect of improved autogenous Mortar self-healing in the alkali-aggregate reaction (AAR). Prismatic Mortar specimens were cast with different contents of polypropylene microfiber and crystalline admixture. The crack-induction method (for subsequent self-healing) was the AAR accelerated Mortar bar test itself. After AAR-testing, the specimens were submitted to wetting and drying cycles to stimulate the self-healing mechanism. These two approaches (AAR and self-healing steps) were alternately repeated four times. The results showed that the Reference Mortar and the mixture with 1% of polypropylene microfiber had the highest and lowest levels of expansion, respectively. The expansion rate was lower for the combined mixtures, although the initial values of length change were high. The visual inspection confirmed that improved autogenous self-healing could close cracks caused by AAR and promote microstructural densification.
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Improvement of repair Mortars using multi-walled carbon nanotubes
Proceedings of the Institution of Civil Engineers - Construction Materials, 2019Co-Authors: Marcelo Henrique Farias De Medeiros, Francielle Dranka, Diego Jesus Souza, Ronaldo A. Medeiros-juniorAbstract:The research reported in this paper focused on the improvement of repair Mortars using multi-walled carbon nanotubes. Compressive strength, squeeze flow and flow-table tests were performed to assess the effects of incorporation of nanotubes on the rheological and strength properties of Mortars. A Reference Mortar and five Mortars with nanotubes were made, with nanotubes sourced from two different manufacturers. It was found that the cementitious composites were stiffer with higher nanotube content and that no more than 0·3% should be used to ensure Mortar fluidity. Regarding the compressive strength, the results indicated that 0·3 and 0·4% of nanotubes increased the strength by 22 and 27%, respectively. However, 0·5% made the Mortar difficult to mix and did not result in increased strength.