Physical effects of natural pozzolana on alkali-activated slag cement

Zeghichi, Leila; Benghazi, Zied

doi:10.1260/1708-5284.8.2.141

Cited by 5 publications

(3 citation statements)

References 6 publications

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“…This may be explained by the difference in the nature of the original aggregates in the concrete wastes used in each study. Aggregates with a high (Ca/Si) ratio, such as limestone, are characterized with high water absorption [41].…”

Section: Figure 8 Porosity and Absorption Of Different Mortar Mixture...mentioning

confidence: 99%

A Comparative Study of Metakaolin/Slag-Based Geopolymer Mortars Incorporating Natural and Recycled Sands

2022

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Great efforts are being made to minimize the negative impact of the Portland cement industry on the environment by using industrial by-products during the manufacture of clinker or by the partial replacement of cement during the preparation of concrete. However, the carbon footprint remains relatively high in addition to the large consumption of natural resources such as sand and other aggregates. A solution to these problems is to completely replace Portland cement with a new generation of mineral binders, commonly known as geopolymers, which have properties similar to those of Portland cement. These binders can be obtained by the alkali-activation of siliceous or aluminosilicate materials. This study aims to develop pozzolanic type binders at room temperature (20°C) from the alkali-activation of aluminosilicate materials based on metakaolin and blast furnace slag at different percentages. Different activators were employed, including solid (NaOH) and liquid (Na2SiO3.nH2O). The optimal mixtures were used for making mortars based on natural sand (NS) and concrete recycled sand (CRS). A comparative experimental study of the physical, mechanical, and microstructural characteristics of the two types of mortars was conducted. Cement mixtures with a high amount of slag and an association of sodium hydroxide and sodium silicate gave the best physico-mechanical properties. A drop in the compressive strength of mortars prepared with CRS was observed after 365 days, but it was still higher than those with NS. The obtained results show the possibility of designing an eco-friendly CRS-based geopolymer mortar that is more resistant than NS-based mortar with a homogeneous and integrated microstructure. Doi: 10.28991/CEJ-2022-08-08-07 Full Text: PDF

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Section: Figure 8 Porosity and Absorption Of Different Mortar Mixture...mentioning

confidence: 99%

A Comparative Study of Metakaolin/Slag-Based Geopolymer Mortars Incorporating Natural and Recycled Sands

2022

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“…e cementitious material is generally ordinary Portland cement (OPC), which aims to make CPB gain strength to support the surface after a certain curing age [16][17][18][19]. Since the backfill cost mainly comes from cementitious materials, it has become a trend to mix OPC with solid wastes such as blast furnace slag and fly ash [20][21][22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Effect of Tailings Fine Content on the Properties of Cemented Paste Backfill from the Perspective Packing Density

Wang

Sun

Wang

et al. 2021

Advances in Civil Engineering

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In order to quantitatively study the influence of tailings fine content on the properties of cemented paste backfill (CPB) and further understand the mechanism of tailings fine content acting, the concept of packing density was introduced in this study. The packing density of each tailings sample was measured by the wet packing method after the samples with various fine contents were prepared. Moreover, CPBs with different tailings fine contents were tested by the mini slump test, rheological test, uniaxial compressive strength (UCS) test, and mercury intrusion porosimetry test. The results demonstrated that the flow spread and UCS both increase first and then decrease with the increase of tailings fine content, while the yield stress shows an opposite trend. The fine content of tailings affects the flowability of fresh CPB mainly through the packing density. When the fine content is high, the influence of the specific surface area of tailings cannot be ignored. The packing density is an important factor affecting the strength of CPB, and there is an obvious linear relationship between the packing density and UCS. The pore structure of CPB samples with different tailing fine contents is significantly different, and the macroscopic packing density changes the strength of CPB by affecting the microscopic pores.

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“…AASFC is composed of 50 per cent FA and 50 per cent GGBS by weight as binder that provide sufficient strength even under ambient curing conditions. If FA content increases beyond 50 per cent, mechanical strength will be reduced in AASFC (Zeghichi and Benghazi, 2011; Wardhono et al , 2015; Aboshia et al , 2017; Palankar et al , 2017; Ridha et al , 2018).…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental studies on sustainable alkali activated concretes at elevated temperatures

Yaragal

Kumar

Abhinav

2019

JSFE

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Purpose To reduce environmental impact caused by excessive use of ordinary Portland cement (OPC) and to mitigate scarcity of base materials such as natural coarse aggregate (NCA), industrial by-products can be carefully used as alternatives to OPC and NCA, in production of concrete. This paper aims to describe the performance of using ground granulated blast furnace slag (GGBS), fly ash (FA) as a complete replacement to OPC and ferrochrome slag (FCS) as replacement to NCA in production of novel FCS based alkali activated slag/fly ash concretes (AASFC) and evaluate their performance at elevated temperatures. Design/methodology/approach Two control factors with three levels each i.e. FA (0, 25 and 50 per cent by weight) and FCS (0, 50 and 100 per cent by volume) as a GGBS and NCA replacement, respectively, were adopted in AASFC mixtures. Further, AASFC mixture specimens were subjected to different levels of elevated temperature, i.e. 200°C, 400°C, 600°C and 800°C. Compressive strength and residual compressive strength were considered as responses. Three different optimization techniques i.e. gray relational analysis, technique for order preference by similarity to ideal solution and Desirability function approach were used to optimize AASFC mixtures subjected to elevated temperatures. Findings As FA replacement increases in FCS based AASFC mixtures, workability increases and compressive strength decreases. The introduction of FCS as replacement to NCA in AASFC mixture did not show any significant change in compressive strength under ambient condition. AASFC produced with 75 per cent GGBS, 25 per cent FA and 100 per cent FCS was found to have excellent elevated temperature enduring properties among all other AASFC mixtures studied. Originality/value Although several studies are available on using GGBS, FA and FCS in production of OPC-based concretes, present study reports the performance of novel FCS based AASFC mixtures subjected to elevated temperatures. Further, GGBS, FA and FCS used in the present investigation significantly reduces CO2 emission and environmental degradation associated with OPC production and NCA extraction, respectively.

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Physical effects of natural pozzolana on alkali-activated slag cement

Cited by 5 publications

References 6 publications

A Comparative Study of Metakaolin/Slag-Based Geopolymer Mortars Incorporating Natural and Recycled Sands

A Comparative Study of Metakaolin/Slag-Based Geopolymer Mortars Incorporating Natural and Recycled Sands

Effect of Tailings Fine Content on the Properties of Cemented Paste Backfill from the Perspective Packing Density

Numerical and experimental studies on sustainable alkali activated concretes at elevated temperatures

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