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Alkali-activated binders have been proposed and have emerged as an alternative to ordinary Portland cement (OPC) binders with acceptable mechanical and durability performances in addition to positive environmental impacts. These alternative binders use a wide range of aluminosilicate precursors, with differing availabilities, reactivities, costs and CO2 emissions. Despite all the studies published on improving the characteristics of these materials in the last decades, some aspects of alkali-activated binders require further investigations. For instance, shrinkage in alkali-activated binders due to the different chemical processes being involved is more complicated than OPC composites and it... 

In this paper, the optimum alkali activator solution properties in alkali-activated pastes based on ground granulated blast furnace slag (GGBFS) and micro-silica (MS) were investigated. For this purpose, sodium hydroxide (NH) solutions with molarities of 8 M, 12 M, and 16 M were prepared and mixed with sodium silicate (NS) solutions at NS:NH ratios of 1.0, 2.5, and 4.0 to produce the final activator solution. Two sets of pastes were manufactured: (1) pastes based on GGBFS, and (2) pastes in which 10% by weight of GGBFS was replaced with MS. The fresh density increased with increasing NH molarity and NS:NH ratio; whereas, the final setting time reduced with an increase in the aforementioned... 

Copper slag (CS) is an industrial waste, which is generally disposed of in landfills, posing threats to the environment. Alternatively, it can be used as natural aggregate replacement in concrete/mortar, however, it results in a significant increase in material density, production and handling cost. The use of crumb rubber in combination with CS can overcome these problems, but there was no prior study on effect of such combination on the properties of alkali activated mortars (AAMs). The primary aim of this study is to address the problem stated above by replacing CS with 5, 10, 15% (by volume) crumb rubber in alkali-activated slag mortars. Furthermore, the effect of pre-treatment of crumb... 

Every year, about a thousand million tires reach the end of their service life, more than half of which are disposed of in landfills. The waste tire rubber has a great potential for application as aggregate phase in production of lightweight concrete/mortar. This study is aimed at evaluating the effects of using crumb rubber (CR) as fine aggregate at replacement ratios of 0–60% (by volume) in alkali-activated slag mortars. Furthermore, polypropylene fibre (PPF) was used at 0.5% and 1% of volume of the mix to enhance the properties of mortar mixes such as flexural strength and shrinkage behaviour. The compressive strength, flexural strength, water absorption, thermal conductivity, drying... 

This study was aimed at evaluating the effects of alkali activator solution and utilization of silica fume (SF) on durability and microstructural characteristics of alkali-activated ground granulated blast furnace slag (GGBFS) pastes. The pastes were activated with sodium silicate (SS) blended with NaOH (SH) solution with molar concentrations of 8 M, 12 M, and 16 M and SS:SH ratios of 1.0, 2.5, and 4.0. The same mixes were prepared with SF as partial replacement of GGBFS at a dosage of 10% by weight. The initial and final water absorption as well as the electrical resistivity of the specimens were measured. The optimal paste fabricated with 12 M NaOH solution and SS:SH ratio of 2.5 showed... 

Prior studies were conducted in an isolated manner for the use of glass powder (GP) either as ordinary Portland cement (OPC) replacement material in blended cement or as a precursor in AAM material. There was no reported literature that made a direct comparison on the properties of blended cement and AAM containing GP with an equivalent mix composition. The present study was aimed to evaluate and compare the effects of GP as a partial precursor on properties of both OPC and alkali-activated slag (AAS) mortars. For this purpose, cement and ground granulated blast furnace slag (GGBFS) was partially replaced with 10%, 20%, 30%, and 40% (by weight) GP in OPC and AAS mortars, respectively. The... 

Every year, about a thousand million tires reach the end of their service life, more than half of which are disposed of in landfills. The waste tire rubber has a great potential for application as aggregate phase in production of lightweight concrete/mortar. This study is aimed at evaluating the effects of using crumb rubber (CR) as fine aggregate at replacement ratios of 0–60% (by volume) in alkali-activated slag mortars. Furthermore, polypropylene fibre (PPF) was used at 0.5% and 1% of volume of the mix to enhance the properties of mortar mixes such as flexural strength and shrinkage behaviour. The compressive strength, flexural strength, water absorption, thermal conductivity, drying... 

This study was aimed at evaluating the effects of alkali activator solution and utilization of silica fume (SF) on durability and microstructural characteristics of alkali-activated ground granulated blast furnace slag (GGBFS) pastes. The pastes were activated with sodium silicate (SS) blended with NaOH (SH) solution with molar concentrations of 8 M, 12 M, and 16 M and SS:SH ratios of 1.0, 2.5, and 4.0. The same mixes were prepared with SF as partial replacement of GGBFS at a dosage of 10% by weight. The initial and final water absorption as well as the electrical resistivity of the specimens were measured. The optimal paste fabricated with 12 M NaOH solution and SS:SH ratio of 2.5 showed... 

Alkali-activated slag (AAS) binder has been recognized as a suitable material for construction applications owing to its low carbon footprint and good mechanical and durability performance. As a promising alternative to the conventional Portland cement binder, it is important to maximize the performance of AAS composites under normal and harsh environmental conditions such as exposure to fire. The use of fibers in a brittle matrix is a well-known approach to enhance the mechanical strength and cracking behavior under thermal loading. In this study, polypropylene fiber (PPF), glass fiber (GF), and basalt fiber (BF) are used at volume fractions of 0.5%, 1%, and 1.5% in AAS mortar mixes. First,... 

Copper slag (CS) is an industrial by-product, which is commonly disposed in engineered landfills. Prior studies have successfully incorporated CS as an aggregate phase in cementitious materials. However, the alkali-activated material (AAM) incorporating CS has been scarcely studied. Specifically, the elevated temperature behavior of AAM with CS has not been investigated previously. The present paper aims to study the effects of elevated temperature treatment on the mass loss and residual strength of alkali-activated slag mortars incorporating 0–100% (by volume) of CS with an incremental step of 20% instead of natural sand. The mass loss, compressive and flexural strengths, and microstructure... 

The authors regret that there was an error in the SEM image presented in Fig. 4(c) of the previously print version of the article. Please refer to the corrected SEM image as presented here. It is noteworthy that this change does not affect any of the conclusions. The authors would like to apologise for any inconvenience caused. © 2021 Elsevier Ltd