Jarosite added concrete along with fly ash: Properties and characteristics in fresh state

SummaryThis paper presents the results of different properties and characteristics of jarosite added concrete along with fly ash during its fresh state. Jarosite is an industrial by product from zinc manufacturing industry obtained through hydrometallurgical process from its sulphide ore. It has been tried to incorporate jarosite in concrete as sand replacement. Different concrete mixtures have been prepared for three water–cement ratios (0.40, 0.45 and 0.50) and 5 jarosite replacement levels (0, 5, 10, 15, 20 and 25%). Cement has been partially replaced (25%) by fly ash in all the concrete mixtures. Density, workability and setting & hardening of fresh concrete has been evaluated and analyzed. Keeping the environmental suitability of concrete in mind, toxicity leaching characteristic potential test has been performed on raw jarosite and concrete samples

Effect of recycled waste glass on the properties of high-performance concrete : A critical review

Solid waste disposal is one of the major environmental concerns. Disposal of waste glass into open areas and landfills is one of the major threats that pollutes the environment in addition to the cases of health hazards around the world. Recycling the discarded glass as a sustainable construction material have received an increasing attention in the construction industry as it may mitigate the greenhouse emissions and potential environmental risks. This paper presents a brief review on the fresh, mechanical and durability properties of normal and high-performance concrete containing waste glass aggregates (WGA). The size, type, replacement ratio of the WGA, in addition to the mixing and curing methods of concrete significantly affects the mechanical and durability characteristics. The concrete containing powdered glass exhibited superior durability properties on account of the refined pore structure and densified microstructure. The findings exhibited that waste glass can be potentially utilised as coarse and fine aggregates in concrete production, along with the advanced recommendations for further studies

Effect of wastewater as sustainable concrete material on concrete performance : A critical review

A massive amount of water has been consumed to produce concrete. The lack of sufficient water for drinking and other essential processes reduces the quantity of water that should be delivered to the people because of the high water consumption by concrete production. All the waste from commercial buildings, households, institutions, and hospitals are known as wastewater. Generally, the water demand is anticipated to increase considerably in the near future. Energy and industry production are expected to witness essential rises in water demand. The enormous quantities of water and generating large quantities of various wastewater from different treatment processes led to exploring different ideas to overcome these issues. One of these ideas is the utilization of wastewater in the construction industry, particularly in concrete mixtures and curing. In the literature, a lack of sufficient studies is obtainable for concrete production from wastewater. This study reviews the chemical composition and physical properties of wastewater and the durability properties of concrete. The treated wastewater from sewage treatment plants (STP) is utilized acceptably for particular utilization. Using treated effluent (TE) in concrete improves cement paste's setting time and compressive strength more than drinking water. The concrete samples containing wastewater recorded 7%–27% lower porosity than control concrete because of the hydration process of cement with time, in addition to the pozzolan reactions. In terms of rapid chloride penetration examination, the authors detected that the samples containing wastewater recorded higher Coulomb charges than that of the control concrete sample without wastewater at 28 curing days because of the high chloride ions in wastewater than that of tap water. The chloride ion penetration increased due to an increase in the domestic wastewater content. Consequently, there is a critical need to improve various processes to adopt and use wastewater in concrete mixtures. This study recommends using a high volume of wastewater to get sustainable concrete with high performance

Sustainable use of palm oil fuel ash as a supplementary cementitious material: A comprehensive review

Cement concrete has been popularly used as a construction material with an approximate annual consumption of 10 billion tons. Increase in urbanization and industrialization increased the demand of concrete materials at recent days. It has been estimated that the cement industry alone generates approximately 6–7% of the total CO2 emissions. These environmental concerns demand the use of alternative renewable and sustainable materials to produce green concrete. Meanwhile, a large amount of agricultural waste, especially palm oil waste is disposed into the open area and landfills, causing serious environmental problems. An estimated 12 million tons of palm oil fuel ash (POFA) is generated in the world per annum. To minimize the passive effects of concrete production using traditional Portland cement, it was recommended by many researchers to adopt the palm oil waste fall-outs as a supplementary cementitious material. It may be considered a suitable and reliable source for better solutions to magnify the sustainability of the construction industry. This paper reviews the potential utilization of POFA as an alternative cementitious material in concrete. The impact of POFA on the fresh, hardened and durability properties of concrete are deliberated, providing a brief of the current knowing about a suitable utilization of POFA as SCM to promote a sustainable environment in the construction industry. The grinding treatment of raw POFA particles significantly enhances the quality of POFA in terms of compressive strength, resistance against aggressive environments and assist in reducing the drying shrinkage of concrete, although there is a tendency to increase the water absorption and delay the hydration heat of cement mortar. The high quantity of SiO2 in POFA enables pozzolanic reaction and delays the setting times with the addition of CaO to produce further C–S–H gels. The utilization of POFA (20%), ultrafine POFA and nano POFA (30%) can produce high strength and durable concrete, proving to be a promising contribution towards the sustainability of the construction industry

The durability of concrete produced from pozzolan materials as a partially cement replacement : A comprehensive review

Recently, the construction industry used innovative, cost-ecofriendly, and efficient materials in infrastructure development to mitigate the negative impact on the environment due to manufacturing Ordinary Portland cement (OPC). Many efforts have been conducted to improve sustainable materials to be used as cementitious material in pozzolanic materials such as fly ash (FA), slag, metakaolin (MK), rice husk ash (RHA), palm oil fuel ash (POFA), silica fume (SF), etc. Therefore, this paper introduced to review the results from previous studies that investigated the influence of waste materials with high pozzolanic materials on the numerous durability properties. The results show many advantages due to using those pozzolanic materials as partial cement replacements for the environment, saving energy and cost, and improving durability. Ground quartz and SF have the highest silica oxide (SiO2) content, it was recorded as higher than 90%, producing more pozzolanic activity than other waste materials. The resistance of the concrete containing POFA against acid and sulfate attacks increased when increasing POFA fineness. Besides, sorptivity values were reduced importantly for the blended concrete samples, the addition of 55% FA in binary blended concrete considerably reduced sorptivity of cement concretes. In addition to that, these pozzolanic materials improved other concrete properties. This paper can be a good base for researchers and construction players to adopt waste materials in improving the durability of concrete. Lastly, numerous possible studies were recommended for future studies

Geopolymer concrete incorporating recycled aggregates: A comprehensive review

Several industrial by-products are extensively used again as a supplementary cementitious material or aggregates in the interest to reduce environmental footprints in terms of energy depletion, pollution, waste disposition, resource depletion, and global warming related with conventional cement. A remarkable quantity of industrial scrap materials, primarily designated as construction and demolition waste from the construction industry, has transformed into crucial apprehension of governments. In the recent past, substantial explorations have been accomplished to appreciate the distinct characteristics of concrete, employing recycled aggregates from construction and demolition waste. Geopolymer composite is a new cementitious material, and it appears to be a potential replacement for conventional cement concrete. This paper summarises the previous research concerning the utilisation of recycled aggregate as a partial or complete supplants for conventional aggregates in geopolymer concrete. The influence of recycled aggregate addition on the fresh and hardened properties of geopolymer concrete is comprehensively reviewed in this paper. The studies suggest significant improvement in the workability on addition of recycled aggregates to geopolymer concrete. However, the addition results in increased water absorption and sorptivity

Abrasion resistance of sustainable green concrete containing waste tire rubber particles

The development of new environmental friendly concretes such as rubberized concrete is being promoted due to the environmental problems created by the waste tire rubber. Every year millions of tires are discarded, thrown away or buried all over the world, representing a very serious threat to the ecology. In this study, we analyse the potential of waste tire rubber particles as a partial substitute for fine aggregates in normal strength and high strength cement concrete and the resistance to abrasion has been measured. Statistical Analysis was carried out to strengthen the results obtained from experiments. The results show that the use of tire rubber particles can improve the abrasion resistance of concrete, and this can ensure its applications in pavements, floors and concrete highways, or in places where there are abrasive forces between surfaces and moving objects. (C) 2016 Elsevier Ltd. All rights reserved

Computer simulations of end-tapering anchorages of EBR FRP-strengthened prestressed concrete slabs at service conditions

This article examines numerically the behavior of prestressed reinforced concrete slabs strengthened with externally bonded reinforcement (EBR) consisting of fiber-reinforced polymer (FRP) sheets. The non-linear finite element (FE) program Abaqus® is used to model EBR FRP-strengthened prestressed concrete slabs tested previously in four-point bending. After the calibration of the computational models, a parametric study is then conducted to assess the influence of the FRP axial stiffness (thickness and modulus of elasticity) on the interfacial normal and shear stresses. The numerical analysis results show that increasing the thickness or the elastic modulus of the FRP strengthening affects the efficiency of the FRP bonding and makes it susceptible to earlier debonding failures. A tapering technique is proposed in wet lay-up applications since multiple FRP layers are often required. It is shown that by gradually decreasing the thickness of the FRP strengthening, the concentration of stress along the plate end can be reduced, and thus, the overall strengthening performance is maximized. The tapering is successful in reducing the bond stress concentrations by up to 15%, which can be sufficient to prevent concrete rip-off and peel-off debonding failure modes. This article contributes towards a better understanding of the debonding phenomena in FRP-strengthened elements in flexure and towards the development of more efficient computational tools to analyze such structures

The effects of nano- and micro-particle additives on the durability and mechanical properties of mortars exposed to internal and external sulfate attacks

In this study, the effects of micro-silica (MS), nano-silica (NS), class C fly ash (FA), and metakaolin (MK) on the durability and mechanical properties of mortars exposed to internal and external sulfate attacks were investigated. For that purpose, mortars were produced from 3 different sands with different ratios of sulfate ions to generate conditions for an internal sulfate attack. Standard curing procedures were applied to all mortar samples for 23 weeks. Furthermore, mortar samples prepared from Sand A, which had the lowest sulfate content, were kept in sodium sulfate and magnesium sulfate solutions to produce an external sulfate attack. When all test results were evaluated together, the most significant contribution to durability and strength among the admixtures was observed to be from NS, which demonstrated an average improvement of 2–10% over MS, which had the second most significant contribution for mortar samples exposed to the most severe internal and external sulfate attacks. When all mixing ratios and tests were considered, the least significant contribution to durability and strength was determined to be from metakaolin. Additionally, when the test data for all days were compared, magnesium sulfate was found to be approximately 1–10% more destructive in comparison to sodium sulfate. Keywords: Nano-silica, Micro-silica, Durability, Mechanical properties, Mortar, Sulfate attac

Analysis on the hazardous jarosite added concrete

This paper attempts to propose a new method for re-use of jarosite in concrete. Jarosite added concrete was studied for different mechanical and durability properties. The experiments were performed in the laboratory and statistical analysis was done using JMP software to predict the models for different test results by the method of least squares. The models were reduced to equations which depend on water-cement ratio, number of days and jarosite replacement ratios. The strength (compressive and flexural tensile) and abrasion resistance was found increasing, however the depth of water penetration and amount of water absorption was reduced with the increased jarosite content in concrete. Chloride Ion Penetration after 28 and 56 days of immersion was calculated and satisfactory results was observed