Potential application of MSWI bottom ash as substitute material in Portland cement concrete: Filler or binder

In recent years, the rapid industrialization and urbanization led to the explosive growth of municipal solid waste incineration (MSWI) bottom ashes (BA) production. However, most of them are directly landfilled, which not only brings environmental burden but also results in loss of potential resources. Present researches have proved that MSWI BA...

Drying shrinkage of alkali-activated slag concrete with natural/recycled aggregates

Each year a large amount of construction and demolition waste (CDW) is generated in the European Union. For sustainability development the CDW is recycled and re-used. To promote the use of CDW, recycled aggregates from CDW were incorporated in alkali-activated concrete (AAC), which mainly consisted of secondary materials or industrial by...

Mitigating the autogenous shrinkage of alkali-activated slag by internal curing

Alkali activated slag (AAS) has shown promising potential to replace ordinary Portland cement as a binder material. Synthesized from industrial by-products, AAS can show high strength, thermal resistance and good durability. However, AAS has been reported to exhibit high autogenous shrinkage. Autogenous shrinkage is a critical issue for building...

A review: The strength influence factors of slag and fly ash based alkali activated materials

Alkali-activated materials(AAM) are known to be environmentally friendly alternatives to cement-based materials because they can potentially reduce greenhouse gas emissions and reutilize industrial by-products. However, the application of AAM is still limited by the lack of mixture design regulation. Unlike cement, the very different chemical...

Modelling of microstructure of ASR influenced cement-based materials

ASR (alkali-silica reaction) is one of the toughest durability problems in engineering. However, the damage induced by ASR is still fairly unpredictable due to the lack of microstructural information of cement-based materials affected by ASR, while the microstructure determines the global performance. In order to fill this gap, a multiscale...

In situ observation of tricalcium aluminate dissolution in water

The nanoscale dissolution flux of tricalcium aluminate (C3A) in flowing water is characterized in situ by Digital Holographic Microscopy (DHM). The pure dissolution of C3A in flowing water with a flow rate of 34 ml·min-1 before the precipitation of hydrated phases only lasted about one quarter of a second, and the pure dissolution rate mostly...

Lattice Boltzmann simulation of chloride transport in alkali-activated slag

In this work, a numerical model is proposed to study chloride transport in alkali-activated materials. This model is based on multiple-relaxation-time lattice Boltzmann method, where particle distribution function is introduced to simulate the chloride binding and diffusion. This model takes into account diffusion, homogenous reaction between...

A molecular dynamics study of N-A-S-H gel with various Si/Al ratios

The understanding of sodium aluminosilicate hydrate (N-A-S-H) gel is still limited due to its complex and amorphous structure. Recently, molecular dynamics simulation has provided a unique opportunity to better understand the structure of N-A-S-H gel from nanoscale. In this work, the N-A-S-H gel structure was obtained by simulating the...

Accelerated carbonation of ordinary Portland cement paste and its effects on microstructure and transport properties

Coupling of carbonation and chlorides ingress mechanisms is very common in concrete under certain exposure conditions such as coastal environments. The aggravation/ mitigation of corrosion by the existence of carbonation lies on the fact that microstructural changes due to carbonation result in changes on the transport properties of the material...

Utilization of biomass fly ash in alkali-activated materials

This paper investigated the feasibility of using biomass fly ash (BFA) to prepare alkaliactivated slag and fly ash paste. The reference mixture was alkali-activated slag and coal fly ash (CFA) paste with a slag-to-coal fly ash ratio of 50/50. In other mixtures, coal fly ash was replaced at 40% and 100% with BFA, respectively. The results showed...

Will ortho-enriched water increase the durability of concrete?

Water molecules exist as two spin isomers, differing by the relative orientation of the nuclear spins of the two hydrogen atoms: either antiparallel (para-water, S=0) or parallel (ortho-water, S=1) [1]. The transition between these nuclear spin states can be achieved through magnetic symmetry breaking via a field gradient across the spins...

Basic properties of cement paste mixed with calcium hydroxide-ettringite composite type expansive additive

In this study, we targeted a calcium hydroxide and ettringite composite-type expansive additive (EA) and obtained the basic characteristics of the EA mixed cement paste in order to create a method for calculating volume expansion based on the hydration reaction of the PCEA system. Expansion strain, setting time, and compressive strength were...

Carbonation rates of alkali-activated and cement based concretes

The reduction of pH from ~12.5 to ~9 by carbonation of the pore solution of reinforced cementbased concrete structures results in the reinforcement corrosion. The rate of carbonation is an important input for design of the concrete cover depth and the service life prediction of reinforced concrete structures because the initiation of...

Simulating human-robot teamwork dynamics for evaluation of work strategies in human-robot teams

To foster resilience in teams operating in complex work domains, design should allow for a range of work strategies as appropriate to context. This paper describes how computational simulation and network visualization of a team’s work can identify feasible work strategies and assess their appropriateness for different contexts. Network...

Roughness Induced Boundary Layer Transition in Incompressible Flow

The fluid dynamics process leading to laminar-turbulent transition behind an isolated roughness element is investigated in the incompressible regime using particle image velocimetry. The study covers the effect of roughness size and geometry on the promotion of transition. The measurement domain covers a large streamwise range from the near wake...

Inorganic powder encapsulated in brittle polymer particles for self-healing cement-based materials

Many types of healing agents have been investigated. These agents are processed in different ways, such as adhesive polymer in capsules or hollow fibre glasses, bacteria in porous aggregates and geo-materials directly incorporated in the cementbased materials. In this study, sodium silicate powder is encapsulated in polystyrene particles ...

Possibility of self-healing by using capsules and vascular system to provide water in cementititious materials

Since self-healing of cracks is able to improve the durability of concrete structures, it has attracted much attention in the recent years. As known, in concrete matrix there are large amounts of cement grains remaining unhydrated, particularly in high performance concrete. Further hydration of these unhydrated cement grains has potential to...