Engineered cementitious composite (ECC) has superior self-healing potential compared to ordinary cement-based materials due to well controlled crack width. The effect of exposure conditions on self-healing behavior of ECC incorporating limestone powder (LP) was investigated in this paper. Four mixes with varying LP contents were used to prepare ECC. Pre-cracked specimens were subjected to three different

This paper investigated the influence of different CO2 concentrations on the microstructural and mechanical development of reactive MgO cement (RMC) concrete. Combination of various analyses revealed the enhancement of hydrated magnesium carbonate (HMC) phases with relatively superior micro-mechanical properties as the CO2 concentration increased from ambient (∼0.04%) to accelerated (5–20%) levels

Expanded Clay Foam Concrete (eC-FC) is a light-weight foam concrete with expanded clay aggregates, which is an important class of building materials, yet its tensile strength ft and fracture toughness KIC cannot be easily measured using small test samples due to its highly heterogeneous microstructures. This study presents a simple closed-form model for quasi-brittle fracture of heterogeneous solids

A new steel fiber reinforced concrete (SFRC) structure is proposed to improve the bond performance between steel rebars and concrete by aligning the limited steel fibers closely around the magnetized rebar, which is achievable to have both adequate steel fibers around rebar for high steel-concrete bonding and appropriate fiber content for good fluidity of concrete. An experimental test is performed

Electromagnetic wave (EMW) pollution impairs the performance of equipment, facilities, information security, and human health. Ordinary, plain cementitious composite has limited EMW-reflecting capacity. To correct this, a macrostructure EMW absorbing element has been developed to reduce EMW pollution. As conventional casting of macrostructures is not cost-effective and lacks quality because of the

In this study, a series of cementitious composite with internal curing agent incorporating ranging from 0% to 30% were prepared to evaluate their autogenous healing performance. The Clinoptilolite Zeolite was utilized as an internal curing compound to replace parts of sand for storing the water inside the cement matrix. The mechanical properties were examined via compressive and splitting tensile tests

Acoustic and thermal comfort play an important role in the building environment. This study investigates ultra-lightweight concrete incorporating Miscanthus fibers as lightweight aggregates to improve sound absorption and thermal insulation properties. Miscanthus fibers (MF) is a kind of sound absorption biomass that can dissipate sound noise thanks to its porous and flexible inner structures and fibrous

In this study, an expansive ultra-high performance concrete (UHPC) was prepared by combining use of lightweight aggregate (LWA) and CaO-expansive agent (EA) for concrete-filled steel tube applications. The coupled effects of LWA and EA on the volume stability, mechanical properties and microstructure of UHPC were systematically evaluated. The expansive stress of the outer wall of UHPC-filled steel

In order to improve the durability of concrete structures, silicate-based impregnant have been used, but the chemical interaction mechanism is not clear. Silicate-based impregnant react with calcium hydroxide, which is formed during the process of cement hydration, and form compounds similar to a calcium silicate hydrate (C–S–H). This paper performs reaction experiments by Ca/Si ratio, and solid state

The use of ordinary Portland cement (PC) as the principal binder in concrete brings with it significant environmental challenges through the consumption of fossil fuels and emission of carbon dioxide (CO2) during cement production. Concrete specimens made with an alkali activated cementitious material (AACM) produced from an alternative binder and conventional Portland cement concrete were exposed

This work investigated the immobilization of municipal solid waste incineration (MSWI) fly ash using spent caustic as alkaline activator and blast furnace slag (BFS) as an additive, in which comparable alkalinity NaOH solution was used as controlling alkaline activator. The leaching behavior of heavy metals and organics in alkali-activated MSWI fly ash-based mortars were characterized by HJ/T 300–2007

3D printed fly ash based geopolymer was prepared with fly ash and quartz sand as main raw materials while slag powder and silica fume as supplementary cementitious materials. In this paper, anhydrous sodium silicate powder was used as activator and ATTAGEL-50 thixotropic thickener was used as 3D printing additive. The effect of slag powder and silica fume on the rheological properties of 3D printed

In this study, municipal solid waste incineration bottom ash (IBA) was reused as fine aggregates to prepare ultra-high performance concrete (UHPC). The effects of IBA on the mechanical properties, workability, hydration, volume stability and microstructure of UHPC were investigated. The experimental results showed that the incorporation of an appropriate amount of IBA could improve the compressive

High-strength, lightweight concrete materials have been widely used in many building structures, while the dynamic behaviors under high-strain-rate loading are not well understood. Two groups of high-strength, lightweight concrete specimens were cast for static and dynamic tests. The compressive strengths and densities of the specimens were 39.6 N/mm2 and 1.3 t/m3, respectively. Specimens with length-to-diameter

Anti-water-penetration techniques are important to raise the durability of cement-based materials (CBMs). Here the water penetration resistances of cement mortars with ethylene-vinyl acetate copolymer (EVA) and styrene butadiene rubber (SBR) were in-situ and non-destructively probed by micro-focus X-ray computed tomography (μ-XCT). Caesium Chloride (CsCl) was mixed in water to enhance the contrast

This study addresses the intrinsic effect of hybrid fibres 3D network on the electrochemical characteristics of Ultra-High Performance Fibre Reinforced Composites (UHPFRC), including experimental investigations and mechanism analysis. Firstly, the matrix of the UHPFRC is fabricated based on the modified Andreasen & Andersen model. Then, three types of fibres (long steel fibre (LSF), short steel fibre

In this study, the effect of maltodextrin on the hydration kinetics of ordinary Portland cement was investigated. Additionally, the impact of maltodextrin on the physical and mechanical properties of cement is further studied via setting time, fluidity and mechanical strength tests which has been conducted with different curing times (16 h, 1 d, 3 d, 28 d). The results revealed the impact on the mechanical

In this study the boundary zone around polypropylene fibres in hardened cement paste was defined in terms of porosity and unhydrated cement particles using the phase contrast tomography with a spatial resolution of 0.637μm within a volume of 1.305×1.305×1.305 mm3. Pores and unhydrated grains were identified from the cement paste made of blended cement by separating them from computed tomography images

This paper aims to investigate drying shrinkage, strength and microstructure of alkali-activated high-calcium fly ash (AAHF) paste by using FGD-gypsum (FGD) and dolomite (DLM) as expansive additives. The 10 M sodium hydroxide combined with sodium silicate solutions were used as alkaline activator for all mixes. The preparation of AAHF paste was divided into 2 steps. First, the study focused on the

A rapid and reliable performance test will enable fast and suitable selection of binder for each service environment. In order to evaluate the possibility of using smaller specimens to accelerate the sulphate resistance tests, Portland cement mortar specimens of sizes 20 × 20 × 160 mm, 25 × 25 × 280 mm and 40 × 40 × 160 mm were continuously immersed in 50 g/l sodium sulphate solution and various physical

This work evaluates the influence of the accelerator type, the cement type and age of exposure on the degradation mechanism and the durability of sprayed mortars subjected to external sulphate attack (ESA). Cores and prisms were extracted from panels sprayed with 8 mortar compositions (with 2 sulphate-resisting cement types and 4 setting accelerators) and then exposed to a sulphate solution at the

Fly ash (FA) concrete has many advantages of enhancing durability even in severe environmental conditions. If the long-term performance can be predicted with higher reliability, it greatly contributes to determination of proper mix proportions in structural design, with further application to practical structures being anticipated. Although the finding that peculiar slow-down hydration of FA in blended

This paper reports on the monotonic and cyclic bending behaviour and damage evolution of steel fibre reinforced concrete (SFRC), by three-point bending tests assessed with acoustic emission (AE) monitoring. Hooked-end fibres are used with 0.25 or 0.5 V% and monotonic, progressive cyclic and variable cyclic loading are applied. The aim is to evaluate AE analysis methods for both monotonic and cyclic

The rise in atmospheric [CO2] globally has consequences on economic infrastructures of concrete such as buildings, bridges, silos, amongst others. The present study employed a natural carbonation prediction (NCP) model to analyse carbonation progression and the service lifespans of concrete infrastructures, based on the forecasted global [CO2] levels for years up to A.D. 2100 (IPCC, 2013). The environmental

Polymer fibers have been commonly used to prevent spalling of ultra-high performance concrete (UHPC) at high temperature. Although different polymer fibers have been adopted in UHPC, the critical properties of polymer fibers required for spalling resistance remained unanswered. This paper investigated the behavior of commonly used polymer fibers, including linear low-density polyethylene (LLDPE), Ultra-high

Carbonation treatment can effectively improve the performance of recycled concrete aggregate and fines due to the reactions of CO2 with CH and C–S–H gel of cement paste. To better understand the mechanisms involved in the performance improvement, the surface properties of carbonated recycled cement paste powder (CRP) and its effect on the rheology, hydration and strength development of cement paste

Fourteen raw slag samples were collected from different steel companies from China, using which setting, mechanical and early-age microstructural behaviours of alkali-activated slag (AAS) cements were investigated. To assess the reaction process between ground granulated blast furnace slag (GGBS) and activator, isothermal calorimetry tests were conducted on three selected AAS pastes for 50 h, while

Geopolymers have been widely applied to pretreat Pb-containing solid wastes due to low carbon footprint and superior stabilization/solidification (S/S) performance. However, the wastes may be exposed to rainwater or water flow during long-term landfill, leading to the decalcification of internal geopolymer structure. Here, the influence of decalcification on the S/S performance of Pb-containing geopolymers

In this study, the efficiency of surface treatment in the calcium sulfoaluminate (CSA) cement-based materials were explored. Several frequently used surface treatment agents (sodium silicate (NS), and magnesium fluorosilicate (MFS), tetraethyl orthosilicate (TEOS), poly-methyltriethoxysilane (PMTS)) were applied on hardened CSA mortar and concrete. The penetration depth of these agents and their influence

This study evaluates the effects of the manufacturing process and fiber reinforcement on low-velocity impact response of the recently developed PVA fiber-reinforced alkali-activated stone wool composites. To this end, reinforced and unreinforced specimens manufactured by hot-pressing were compared with those oven curing. The results revealed a similar impact response for the hot-pressed composite produced

In the sol–gel science, the influence of chemical aging on the fundamental water permeability remains open regarding to the durability performance of cement-based material. To reveal the pure effect of chemical aging, the water permeability and related micro-structural characteristics are measured on water-saturated mature mortars, whose aging is accelerated through heat treatment under water. It is

Cement based material structures have to be managed over long periods. However, they are exposed to numerous loadings and present time-dependent deformations. In addition, the material is a porous medium in which pore pressure has an impact on macroscopic behaviour. The goal of this study is to better forecast the long term behaviour of cement based materials taking into account interactions between

Strain-hardening cement-based composites (SHCC) reinforced additionally with continuous textile reinforcement exhibit a high tensile strength, ductility and low crack width up to failure localization, being suitable as strengthening layers on structural elements subject to impact loading. The quasi-static tensile properties of such composites are usually derived on long, planar specimens, as dictated

Concrete generally deforms and cracks in a non-uniform manner under drying-induced stress. This study used the lattice fracture model to simulate the drying-induced non-uniform deformations, stresses, and micro-crack propagation in concrete. Experiments were designed to validate the lattice fracture model, wherein the drying-induced non-uniform deformations and micro-crack patterns in concrete were

The objectives of this study are to examine the rheological and mechanical property of fresh CTB incorporating silica fume (SF) at low temperature and in an effort to assess the applicability of using SF as a partial cement replacement. The cement replacement level was set at 0% (control), 2.5%, 5.0% and 10.0% by weight. Furthermore, the effect of curing temperature (−12, −1, 6, and 20 °C) on time-dependent

Recycled powder (RP) is the main by-product in the reclamation of construction and demolition (C&D) waste. A body of literature on the use of RP as supplementary cementitious materials (SCMs) in concrete is currently available, whereas a detailed review on the properties of RP concrete has been lacking until now. Considering that concrete and brick waste account for a large proportion of C&D waste

Formation of cracks represents one of the major causes of concrete deterioration, which can lead to durability and safety issues. In this work, a novel crack closure system is developed, using polyethylene terephthalate (PET) polymer fibres embedded in a mortar mix. The PET polymer has shape memory properties and shrinks upon thermal activation, if free to do so, or otherwise exert shrinkage restraint

Recently developed reactivity tests for supplementary cementitious materials (SCMs) have shown the ability to differentiate between inert and reactive materials. Two promising SCM reactivity tests were used to study ten different SCMs. The first method involves quantifying the heat release, bound water, and calcium hydroxide consumption of SCMs in a simulated pore solution (modified R3 test), and the

This study aims to investigate the cracking potential of alkali-activated slag (AAS) and alkali-activated slag-fly ash (AASF) concrete subjected to restrained autogenous shrinkage. Temperature Stress Testing Machine (TSTM) is utilized, for the first time, to monitor the stress evolution and to measure the cracking time of alkali-activated concrete (AAC) under restraint condition. The stresses in AAS

This study pioneers the use of cellulose nanofibres (CNF) as a means to restricting the chloride-ion ingress in cement based systems. Three CNF variants, differing in their carboxylate content from 0.13 to 1.13 mmol/g of the nanofibre, were introduced to paste and mortar mixtures alike, at up to 1.2% by volume fraction of the dry nanofibre. The reference mixture was a plain system, prepared with CSA

In this study, diatomite was used in cement mortar to improve the frost resistance durability. Experimental results showed that using diatomite instead of a small amount of silica fume (such as the samples in D-33.3%) can effectively enhance the frost resistance of cement mortar. To comprehensively understand the modification mechanism of diatomite, pore structure of cement mortar considering the effect

Pavement in tunnels requires specific properties and functions. In this study, bright and slip-proof Engineered Cementitious Composites (ECCs) with visible light activated photo-catalysis properties are developed for pavement applications in tunnels. A carbon-modified TiO2 is used to engage a visible light activated photo-catalysis property while white fine aggregates are included to enhance the skid

Due to the small dimensions of interfacial transition zone (ITZ) in concrete, the measurement of ITZ is subjected to difficulties of deformation measuring at macro-scale and loading at micro-scale. This work presents a coupled strategy between the scanning electron microscope (SEM) technology and the digital image correlation (DIC) method to experimentally study the mechanical properties and thickness

The application of seawater as the mixing water in concrete production could mitigate the increasing demand for fresh water in concrete production associated with the continuously increasing offshore infrastructures. Understanding the key factors that influence the properties of seawater-mixed cementitious materials could promote the application of seawater during concrete preparation. A comprehensive

Underwater cast and cured geopolymers with Si/Al ratios of 1.78 and 2.00, synthesized from Class C fly ash and metakaolin, were characterized by X-ray diffraction, X-ray fluorescence, scanning electron microscopy, and unconfined compression, to understand the interactions between the geopolymer slurry and curing saline solutions and pertinent effects on its strength development. Slurries of geopolymers

This study presents the use of waste glass (WG) in pervious concrete, aiming to maximizing the reuse of WG in concrete. The effect of WG aggregate replacement and aggregate to binder ratio (A/B) on the mechanical properties, permeability, thermal conductivity, volume stability and pore structure were determined. The microstructures with and without immersing in 1 M NaOH 80 °C solution were also characterized

Current technical knowledge on the rheological behavior of cemented paste backfill (CPB) that contains nano-silica (nS) at different curing temperatures is insufficient. However, the assessment and an understanding of the yield stress and viscosity of CPB with nS added at the early ages are critical for using CPB technology in underground mines located in cold or warm regions and/or for deep mining

The objective of this study is to clarify optimal conditions for suppressing the expansion of ASR-deteriorated concrete by pressure-injecting a lithium nitrite solution. To investigate the ASR-mitigating effect of lithium nitrite, concrete mixtures with two types of reactive aggregates were impregnated with lithium nitrite by pressurized injection at three steps of ASR. The effects of different timings

The durability of concrete structures is crucial for their sustainable use; therefore, this study aims to provide a method for their service life prediction. The first stage of the study presents an in-situ air permeability measurement approach to evaluate the carbonation resistance of steam-cured concrete. The changes in properties of steam-cured concrete, including moisture content, air permeability

The performance of ternary binders using lime, metakaolin (MK) and gravel wash mud (GWM) powders is studied for the development of novel lime-pozzolan pastes. This study examines the influence of varying mixture proportions using different types and compositions of lime powders and GWM at different treatment levels on the mechanical properties of lime-MK-GWM pastes. Various characterisation techniques

Strain Hardening cementitious composites (SHCCs) have been known to produce excellent crack width control and very good tensile strain capacity. As a result, strategically introducing SHCCs would lead to significant carbon saving through the creation of structures that are durable and could potentially undergo autogenous self-healing. However, for wider acceptability of any new material requires long

In this work, a methodology is presented in order to assess the microstructure of Portland Cement through advanced characterisation. Nanoindentation is used to determine reduced elastic modulus and hardness, which are involved in the design of construction materials. Elemental mapping and X-ray scanning microtomography were also used to establish structure-property relations through porosity distribution

Structural health monitoring has contrived a path for ascertaining the condition of any structure under operating or critical loads. This paper investigates a possible application of the electro-mechanical impedance (EMI) technique in diagnosing high-cycle and low-strain fatigue damage in the reinforced concrete (RC) structures. The experimental study is conducted on a RC frame structure of overall

Electrochemical impedance spectroscopy (EIS) provides a potential approach to evaluate the overall breakage situation of self-healing microcapsules in cementitious materials. In this paper, EIS responses of cementitious mortar with insulative epoxy microparticles and conductive graphite microparticles, which was prepared for simulating the breakage situation of the microcapsules, were determined. An

This paper presents an investigation on high temperature performance of dry-mix and wet-mix concretes using 0–100% glass aggregates to replace river sand. The thermal conductivity at room temperature and the compressive strength before and after exposure to elevated temperatures were evaluated. The dry-mix and wet-mix concretes with the content of 100% glass aggregates were examined by X-ray μCT, microhardness

Lime-activated fly ash cementitious materials are widely used as masonry cement and autoclaved building materials. This study investigated the effects of MgO on the microstructure and properties of the fly ash/cement-based pastes under hydrothermal conditions. The activator (i.e., CaO + MgO) was fixed at 17 wt%, and CaO was replaced with MgO at 0–30 wt%. The properties assessed were compressive strength