Interface bonding properties of polyvinyl alcohol (PVA) fiber in alkali-activated slag/fly ash

This paper presents an experimental study on the interface bonding properties of polyvinyl alcohol (PVA) fiber in alkali-activated slag/fly ash (AASF) pastes. Three interface bonding properties (i.e., the chemical bonding energy Gd, the initial frictional bond strength τ0, and slip-hardening behavior) were determined using single-fiber pullout...

Fresh properties of limestone-calcined clay-slag cement pastes

Formulation of quaternary blended system containing ordinary Portland cement or clinker, slag, limestone and calcined clay (LC2) appeared to be a viable approach to developing low-clinker cements without severely sacrificing mechanical performance at later ages. This paper investigates the effect of two material parameters, i.e., LC2-to-slag...

Micromechanics-guided development of strain-hardening alkali-activated composites: Towards a low-carbon built environment

Alkali-activated Materials (AAMs), including those classified as geopolymer, are obtained through the reaction between a solid precursor and an alkaline solution. Compared with ordinary Portland cement (OPC) binders, these materials maintain comparable mechanical properties but have the advantage of reducing greenhouse gas emissions and...

Desulphurisation in 21st century iron- and steelmaking

In this PhD thesis, the desulphurisation in 21st century iron- and steelmaking is investigated. The current state of the art in sulphur removal in ironmaking and oxygen steelmaking is discussed (Part I of this thesis) and optimisation of the hot metal desulphurisation (HMD) slag, which is an important aspect of present day desulphurisation, is...

Molecular dynamics and experimental study on the adhesion mechanism of polyvinyl alcohol (PVA) fiber in alkali-activated slag/fly ash

This paper aims to study the adhesion mechanism of polyvinyl alcohol (PVA) fiber within alkali-activated slag/fly ash (AASF) matrix using molecular dynamics (MD) simulation in combination with systematic experimental characterization. The adhesion of PVA to C-(N-)A-S-H gel with different Ca/(Si+Al) and Al/Si ratios was modeled using MD...

Fracture properties and microstructure formation of hardened alkali-activated slag/fly ash pastes

This study presents a comprehensive experimental investigation on the fracture properties of hardened alkali-activated slag/fly ash (AASF) pastes in relation to the microstructure formation and reaction product composition. The main reaction product in AASF is C-(N-)A-S-H gel along with minor hydrotalcite phase, with the polymerization of C-...

Effect of metakaolin on the autogenous shrinkage of alkali-activated slag-fly ash paste

The high autogenous shrinkage of alkali-activated materials made from slag and fly ash is recognised as a major drawback with regard to the use as construction materials. In this study, metakaolin was introduced into the alkali-activated slag-fly ash (AASF) paste to mitigate the autogenous shrinkage. The shrinkage mitigation mechanism of...

Elephant skin formation on UHPC surface: Effects of climatic condition and blast furnace slag content

Ultra-high performance concrete (UHPC), which typically contains extremely high superplasticizer amount, tends to render a special type of dense surface layer, especially under drying conditions. Even if the inner side of fresh UHPC is still in a flowable nature, the top surface of the concrete which is exposed to ambient conditions renders a...

Cracking Potential of Alkali-Activated Concrete Induced by Autogenous Shrinkage

Alkali activated concrete (AAC) has not received broader industry acceptance, one reason of which lies in the uncertainties in the durability against shrinkage and potential cracking. Many studies reported that AAC exhibit larger autogenous shrinkage than OPC concrete. However, it is unable to deduce that AAC should show higher cracking...

Micromechanics-guided development of a slag/fly ash-based strain-hardening geopolymer composite

Strain-hardening geopolymer composite (SHGC) lately emerged as a promising alternative to traditional strain-hardening cementitious composite with added advantages of industrial by-product utilization and enhanced sustainability. However, as the design of SHGC requires multi-factor optimization, the application of traditional trial-and-error...

Isothermal calorimetric study on the heat evolution and the apparent activation energy of alkali-activated slag/fly ash pastes

Alkali-activated slag/fly ash (AASF) as an environmental-friendly binder system for construction materials has recently attracted great attention from both academic and industrial communities. Towards its wider engineering application, it is crucial to have a better understanding of the temperature induced effects by different curing regimes and...

Mitigating the autogenous shrinkage of alkali-activated slag by metakaolin

This study investigates the effectiveness of metakaolin (MK)in mitigating the autogenous shrinkage of alkali-activated slag (AAS). It is found that the autogenous shrinkage of AAS paste can be reduced by 40% and 50% when replacing 10% and 20% slag with MK, respectively. By providing additional Si and Al, and decreasing the pH of the pore...

Coupled thermodynamic modelling and experimental study of sodium hydroxide activated slag

In previous researches, the thermodynamic modelling of alkali-activated slag was conducted as a function of the degree of reaction of slag, which makes it difficult to compare the modelling results with the experimental results in a time scale. In this study, the reaction kinetics of sodium hydroxide activated slag was studied using...

Innovative Glass Recipes Containing Industrial Waste Materials

The growth of the industrial production generates a high volume of waste materials. These products have a significant impact on the environment. Therefore, the valorization of industrial wastes, especially those produced in huge quantities, is an important social and ecological issue. Waste reuse and recycling could help to develop new...

Waste glass as partial mineral precursor in alkali-activated slag/fly ash system

The feasibility of a waste glass powder residue (GP) from glass recycling as partial mineral precursor to produce alkali-activated materials is investigated. GP served as powder coal fly ash (PCFA) replacement within a reference system composed of 50% PCFA and 50% ground granulated blast furnace slag (GGBS). Compared with PCFA, GP was better...

Microstructural and Mineralogical Analysis of Alkali Activated Fly Ash-Slag Pastes

The performances of alkali activated materials (AAM) are strongly related to their microstructures. The microstructure development is mainly affected by chemistry of the primary raw materials. In the present study the influence of different proportions of fly ash and slag (100:0, 70:30, 50:50, 30:70, 0:100 wt.%, named S0, S30, S50, S70, S100,...

Durability of alkali-activated fly ash and slag concrete

Alkali-activated materials (AAM) have received increasing interest during the past few decades due to their environmental and technological advantages. However the durability of these binders is still considered as an unproven issue that needs to be addressed before their commercial adoption and large-scale production. The present work is...

Reaction Kinetics and Thermodynamic Modeling of Sodium Hydroxide Activated Slag Paste

The technology of alkaline activation of calcium aluminosilicate materials, as an alternative to Portland cement to produce a clinker-free material, can address the energy and environmental concerns associated with Portland cement production. As this technology attracts more and more attention in recent years, there are increasing researches...