The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

Rosário Veiga - One of the best experts on this subject based on the ideXlab platform.

  • Reduction of Cement Content in renderings with fine sanitary ware aggregates
    Materials and Structures, 2016
    Co-Authors: C. Farinha, Rosário Veiga, Jorge De Brito, J. Lucas
    Abstract:

    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).

  • reduction of the Cement Content in rendering mortars with fine glass aggregates
    Journal of Cleaner Production, 2015
    Co-Authors: Renata Oliveira, Jorge De Brito, Rosário Veiga
    Abstract:

    Abstract The viability of the reduction of the Cement Content of coating mortars with simultaneous incorporation of very fine glass aggregates, without jeopardizing their functional performance, is discussed here. The use of these modified mortars has both environmental and economic potential advantages. In fact less energy is needed to produce Cement and the direct cost of mortar production is lower. To evaluate the eventual pozzolanic properties of glass fines an experimental programme was followed comprising a series of tests to characterize the behaviour of these mortars in terms of mechanical strength, water-related behaviour, durability and other properties. The results were extremely positive, well above initial expectations. As a matter of fact, it was clearly demonstrated that the mortar with 1:5 Cement:aggregate (considering aggregate as sand + glass fines) ratio instead of 1:4 and 20% incorporation of fine glass aggregates complies with all the requirements to be used as a coating mortar. Since screening of construction and demolition waste and solid urban waste is presently established, it is possible to crush glass waste and upscale the production of pre-mixed mortars with glass incorporation. This will allow a reduction of the Cement Content of these modified mortars and result in environmental benefits, both in terms of energy needed to produce Cement and corresponding emissions to the atmosphere, and reduction of dumped waste.

  • Reduction of the Cement Content in mortars made with fine concrete aggregates
    Materials and Structures, 2014
    Co-Authors: Mariana Braga, Jorge De Brito, Rosário Veiga
    Abstract:

    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.

Maciej Urban - One of the best experts on this subject based on the ideXlab platform.

  • Low Cement Content SCC (Eco-SCC) – the alternative for ready-mix traditional concrete
    MATEC Web of Conferences, 2018
    Co-Authors: Maciej Urban
    Abstract:

    Self-Compacting Concrete (SCC) is often regarded for in-situ applications as a more expensive and less environmentally friendly version of traditional concrete for use in places where the latter is highly inconvenient for various reasons. To counteract this belief, a new type of SCC has been proposed, called Eco-SCC or green-SCC. In comparison to typical SCC this building material has lower powder Content resulting in low Cement Content and a slightly lower paste volume. The disadvantage of this approach is high water Content and low viscosity resulting in high vulnerability of fresh concrete to sedimentation. Additionally, comparing to EN-206 limits, mixes with too low Cement Content are often obtained. This is why a research program has been undertaken to check the possibility of obtaining fresh Eco-SCCs of higher viscosity, thereby fulfilling all EN-206 requirements. It was possible to obtain concretes of C25/30-C35/45, SF2, VF2, PL2, containing 265-300 kg/m 3 of Cement and 165-190 kg/m 3 of water owing to the use of limestone powder and typical rounded aggregate of local origin with very low sand to a total aggregate ratio of s/a = 0.4. Based on Global Warming Potential (GWP) analysis, a modification of Eco-SCC definition is proposed: Eco-SCC is an SCC having Cementitious materials volumetric Content no greater than 100 dm 3 /m 3 (or mass Content no greater than 315 kg/m 3 ).

  • low Cement Content scc eco scc the alternative for ready mix traditional concrete
    MATEC Web of Conferences, 2018
    Co-Authors: Maciej Urban
    Abstract:

    Self-Compacting Concrete (SCC) is often regarded for in-situ applications as a more expensive and less environmentally friendly version of traditional concrete for use in places where the latter is highly inconvenient for various reasons. To counteract this belief, a new type of SCC has been proposed, called Eco-SCC or green-SCC. In comparison to typical SCC this building material has lower powder Content resulting in low Cement Content and a slightly lower paste volume. The disadvantage of this approach is high water Content and low viscosity resulting in high vulnerability of fresh concrete to sedimentation. Additionally, comparing to EN-206 limits, mixes with too low Cement Content are often obtained. This is why a research program has been undertaken to check the possibility of obtaining fresh Eco-SCCs of higher viscosity, thereby fulfilling all EN-206 requirements. It was possible to obtain concretes of C25/30-C35/45, SF2, VF2, PL2, containing 265-300 kg/m 3 of Cement and 165-190 kg/m 3 of water owing to the use of limestone powder and typical rounded aggregate of local origin with very low sand to a total aggregate ratio of s/a = 0.4. Based on Global Warming Potential (GWP) analysis, a modification of Eco-SCC definition is proposed: Eco-SCC is an SCC having Cementitious materials volumetric Content no greater than 100 dm 3 /m 3 (or mass Content no greater than 315 kg/m 3 ).

Joachim Schulze - One of the best experts on this subject based on the ideXlab platform.

  • influence of water Cement ratio and Cement Content on the properties of polymer modified mortars
    Cement and Concrete Research, 1999
    Co-Authors: Joachim Schulze
    Abstract:

    The compressive strength of modified and unmodified mortars depends on water-Cement ratio and, to a lesser extent, on the Cement Content of the mortars. The flexural strength of unmodified mortars responds only slightly to modification of water-Cement ratio or Cement Content. With polymer modification of the mortars, the influence of the variation is increased. There is only a minor influence of water-Cement ratio and Cement Content on the adhesion strength of the modified mortars on concrete slabs. Only in wet conditions is there an additional effect at high Cement Contents and lower water-Cement ratios. Shrinkage and water absorption are a function of water-Cement ratio and Cement Content.

Jorge De Brito - One of the best experts on this subject based on the ideXlab platform.

  • Reduction of Cement Content in renderings with fine sanitary ware aggregates
    Materials and Structures, 2016
    Co-Authors: C. Farinha, Rosário Veiga, Jorge De Brito, J. Lucas
    Abstract:

    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).

  • reduction of the Cement Content in rendering mortars with fine glass aggregates
    Journal of Cleaner Production, 2015
    Co-Authors: Renata Oliveira, Jorge De Brito, Rosário Veiga
    Abstract:

    Abstract The viability of the reduction of the Cement Content of coating mortars with simultaneous incorporation of very fine glass aggregates, without jeopardizing their functional performance, is discussed here. The use of these modified mortars has both environmental and economic potential advantages. In fact less energy is needed to produce Cement and the direct cost of mortar production is lower. To evaluate the eventual pozzolanic properties of glass fines an experimental programme was followed comprising a series of tests to characterize the behaviour of these mortars in terms of mechanical strength, water-related behaviour, durability and other properties. The results were extremely positive, well above initial expectations. As a matter of fact, it was clearly demonstrated that the mortar with 1:5 Cement:aggregate (considering aggregate as sand + glass fines) ratio instead of 1:4 and 20% incorporation of fine glass aggregates complies with all the requirements to be used as a coating mortar. Since screening of construction and demolition waste and solid urban waste is presently established, it is possible to crush glass waste and upscale the production of pre-mixed mortars with glass incorporation. This will allow a reduction of the Cement Content of these modified mortars and result in environmental benefits, both in terms of energy needed to produce Cement and corresponding emissions to the atmosphere, and reduction of dumped waste.

  • Reduction of the Cement Content in mortars made with fine concrete aggregates
    Materials and Structures, 2014
    Co-Authors: Mariana Braga, Jorge De Brito, Rosário Veiga
    Abstract:

    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.

Yohannes L Yaphary - One of the best experts on this subject based on the ideXlab platform.

  • reduction in Cement Content of normal strength concrete with used engine oil ueo as chemical admixture
    Construction and Building Materials, 2020
    Co-Authors: Yohannes L Yaphary
    Abstract:

    Abstract In this study, the coupling effects of admixing a used engine oil (UEO) and reducing the Cement paste Content on the properties of a normal strength concrete were investigated. Initially, various tests were performed to determine the effect of the admixed UEO on the properties (i.e. workability, air Content, setting times, strengths, drying shrinkage, and freezing and thawing (F–T) durability) of the reference concrete (formed in accordance with ASTM C494). Based on the acquired knowledge regarding the aforementioned effects, the chemical-admixture type of the UEO was evaluated. The UEO largely complies with the ASTM C494 type A water-reducing admixture specifications. The admixed UEO can facilitate the production of concrete with 9.4% less Cement Content than that in the reference concrete, but with comparable properties. This study provides a basis for realizing a more economical and eco-friendly production of concrete by both reducing its Cement Content and admixing UEO.