An investigation of high-volume fly ash concrete blended with slag subjected to elevated temperatures

Rashad, Alaa M.

doi:10.1016/j.jclepro.2015.01.031

Cited by 114 publications

(31 citation statements)

References 30 publications

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“…In the construction industry, research and development on alternative binders to Portland cement (PC) have been conducted for decades [2] to reduce the demand for PC, which accounts for about 8% of global CO 2 emissions during its production [3,4]. Nevertheless, the demand is steadily increasing [5][6][7]. As an effort to mitigate global warming, eco-friendly construction materials should be more widely used.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Material Properties of Lime-Activated Slag Mortar from Intensified Pozzolanic Reaction and Pore Filling Effect

et al. 2018

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To utilize alkali-activated materials widely, this study investigates the effects of an intensified pozzolanic reaction and pore filling by silica fume on various material properties of lime-activated slag mortar. Although ground-granulated blast-furnace slag is classified as a cementitious material, it commonly requires an activator to enhance the performance of structural materials. In the first step of the improvement strategy, slag reaction is activated by hydrated lime. Next, silica fume is added to densify the microstructure by the physical pore filling effect and/or the pozzolanic reaction that additionally forms hydration products. This increased the compressive strength by 18% at 28 days and by 25% at 91 days under ambient curing condition, mainly due to the physical effect. Moreover, elevated temperature curing for three days was highly effective to further improve the strength, and to accelerate strength development. This is because both the physical effect and the chemical reaction are effective at the high temperature curing condition. The conducted microstructural investigation provided the evidence for the intensified pozzolanic reaction and pore filling effect, both of which are closely related to the mechanical properties. It is also found that the use of silica fume positively contributes to the dimensional stability. Since the developed material exhibits high strength (>40 MPa after 14 days) without Portland cement or highly toxic chemicals, it can be practically used as an eco-friendly structural mortar.

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Section: Introductionmentioning

confidence: 99%

Enhancement of Material Properties of Lime-Activated Slag Mortar from Intensified Pozzolanic Reaction and Pore Filling Effect

et al. 2018

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“…Besides this, utilization of supplementary cementitious materials (SCM) such as fly ash and blast furnace slag to partially replace cement was found to be useful in reducing the strength deterioration of cement-based materials that were exposed to high temperatures [8,9]. For instance, it was revealed that in concrete containing fly ash, the compressive strength could be increased at elevated temperature of 400°C whereas lower compressive strength loss or better strength retention was also found upon exposure to elevated temperature of 800°C, as reported by Rashad [10] and Seleem et al [11], respectively. At these elevated temperatures, as there was no explosive spalling damage, the concrete could exhibit residual strength and the improvement in the concrete containing fly ash was attributed to the possible formation of tobermorite and new mineral compounds at the temperatures of 400 and 800°C, respectively.…”

Section: Introductionmentioning

confidence: 78%

“…The hydration products hence could fill up the pores within the composite and increase its bond strength [24]. It was reported that the additional hydration product produced could be tobermorite, which was much stronger than calcium silicate hydrate gel, and this was credited to the increase in compressive strength of concrete containing fly ash at 400°C [10].…”

Section: Residual Strengthmentioning

confidence: 99%

Behaviour of fibre-reinforced cementitious composite containing high-volume fly ash at elevated temperatures

Loh

Tan

et al. 2018

Sādhanā

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This research describes the properties of acrylic fibre-reinforced cementitious composite containing high-volume fly ash. In this investigation, the fly ash content (30% and 60%) and the acrylic fibre dosage (0%, 1% and 2%) were varied. Increased content of fly ash in the composite was found to be able to partially compensate the reduction in workability caused by the inclusion of fibres. On the other hand, although the use of fibres had minimal influence on the compressive strength, the fibres could significantly enhance the flexural strength of the composite, particularly in the composite containing higher fly ash content. At elevated temperatures, it was found that the inclusion of acrylic fibres was beneficial in the composite with higher fly ash content, as demonstrated by the increased strength retention and reduced spalling damage at elevated temperature.

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“…Therefore, using an eco-friendly concrete, which utilizes RCA instead of NCA, or utilizes waste SCMs as one of its ingredients to partially replace cement, might have a pivotal role in creating a facility to improve the structural knowledge and maintaining a safe ecological and economical solution. Also, the issue of disposing of these by-products into landfills is a major environmental problem, as they contain a significant amount of leachable toxic elements, which can cause ecological harm to the water, soil, and air [ 13 ].…”

Section: Literature Reviewmentioning

confidence: 99%

“…Furthermore, in the last decade, the cement industry has become the second-fastest growing industry in releasing CO 2 emissions due to the growing worldwide demand for concrete [ 7 ]. Meanwhile, recent statistics indicated an annual worldwide generation of slag and fly ash (FA) wastes of around 270 to 320 million tons and 1 billion tons, respectively [ 13 , 14 ]. Moreover, in the United States and Norway, the annual output of silica fume (SF) was estimated to be of the order 2 × 10 5 to 5 × 10 5 tons [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Green Concrete for a Circular Economy: A Review on Sustainability, Durability, and Structural Properties

et al. 2021

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A primary concern of conventional Portland cement concrete (PCC) is associated with the massive amount of global cement and natural coarse aggregates (NCA) consumption, which causes depletion of natural resources on the one hand and ecological problems on the other. As a result, the concept of green concrete (GC), by replacing cement with supplementary cementitious materials (SCMs) such as ground granulated blast furnace slag (GGBFS), fly ash (FA), silica fume (SF), and metakaolin (MK), or replacing NCA with recycled coarse aggregates, can play an essential role in addressing the environmental threat of PCC. Currently, there is a growing body of literature that emphasizes the importance of implementing GC in concrete applications. Therefore, this paper has conducted a systematic literature review through the peer-reviewed literature database Scopus. A total of 114 papers were reviewed that cover the following areas: (1) sustainability benefits of GC, (2) mechanical behavior of GC in terms of compressive strength, (3) durability properties of GC under several environmental exposures, (4) structural performance of GC in large-scale reinforced beams under shear and flexure, and (5) analytical investigation that compares the GC shear capacities of previously tested beams with major design codes and proposed models. Based on this review, the reader will be able to select the optimum replacement level of cement with one of the SCMs to achieve a certain concrete strength range that would suit a certain concrete application. Also, the analysis of durability performance revealed that the addition of SCMs is not recommended in concrete exposed to a higher temperature than 400 °C. Moreover, combining GGBFS with FA in a concrete mix was noticed to be superior to PCC in terms of long-term resistance to sulfate attack. The single most striking observation to emerge from the data comparison of the experimentally tested beams with the available concrete shear design equations is that the beams having up to 70% of FA as a replacement to OPC or up to 100% of RCA as a replacement to NCA were conservatively predicted by the equations of Japan Society of Civil Engineers (JSCE-1997), the American Concrete Institute (ACI 318-19), and the Canadian Standards Association (CSA-A23.3-14).

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An investigation of high-volume fly ash concrete blended with slag subjected to elevated temperatures

Cited by 114 publications

References 30 publications

Enhancement of Material Properties of Lime-Activated Slag Mortar from Intensified Pozzolanic Reaction and Pore Filling Effect

Enhancement of Material Properties of Lime-Activated Slag Mortar from Intensified Pozzolanic Reaction and Pore Filling Effect

Behaviour of fibre-reinforced cementitious composite containing high-volume fly ash at elevated temperatures

Green Concrete for a Circular Economy: A Review on Sustainability, Durability, and Structural Properties

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