The interfacial bonding between steel fibers and Ultra-High Performance Concrete (UHPC) matrix is pivotal for the mechanical properties in extreme environments. Herein, a surface nanoengineering approach using the sol-gel method was reported to enhance the resistance of fiber bonding to varying cryogenic and elevated exposures (−170 °C to 200 °C). Additionally, the interfacial bonding and failure of

To enhance the safety and functionality requirements of engineering structures, carbon nanotubes are used to improve the performance of concrete. However, their high cost limits their large-scale application. In this study, industrial multi-walled carbon nanotubes (IMWCNT) were employed to ultra-high performance concrete (UHPC) to achieve a balance between nanomodification and economy. The effects

This study explores the feasibility of NaCl based magnesium phosphate cement (NaCl-MPC) composites as a solid electrolyte for energy storage applications by analyzing the physical, mechanical, hydration and electrochemical properties of composites. The results indicated that the incorporation of NaCl greatly improved the mechanical properties and ionic conductivity of composites, demonstrating enhanced

A ductile oil well cement paste (OWCP) with lower autogenous shrinkage is of paramount importance to the integrity of cement sheath under downhole condition. Taking advantage of multiple experimental tests and a micromechanical model, the hybrid effects of nano-rubber (NR) and carbon nanotubes (CNTs) on the mechanical properties, autogenous shrinkage, hydration behavior and microstructure of OWCP were

Engineered geopolymer composites (EGC) are promising alternatives to highly ductile cement-based composites, whereas effectively balancing the strength and ductility of most developed EGC mixes is challenging. This study systematically evaluated the feasibility of incorporating nano-silica (NS) particles to address the problem of balancing strength and ductility in EGC, aiming to develop EGC with extraordinary

In this study, we explored the potential of microbiologically induced calcite precipitation (MICP) for enhancing the microstructural integrity of waste concrete fines (WCF). Traditionally, ureolytic bacteria, such as Sporosarcina pasteurii, have been widely used in MICP due to their ability to produce calcium carbonate via urea hydrolysis, but this process generates ammonia, raising environmental concerns

Microbial induced concrete corrosion (MICC) is the main deterioration mode of concrete corrosion in concrete wastewater transportation system. Protective coating is one of the commonly used microbial corrosion protection technologies for concrete. In this study, the effects of CuSO4 concentration and pH value of electroless plating solution on the preparation of copper-plated hardened cement paste

Most literature has focused on the effect of shrinkage-reducing admixture (SRA) in shrinkage mitigation resistance of concrete. This study aims to examine the impact of SRA on the efficiency of macro synthetic fibers (MSF) in enhancing the flexural post-cracking behavior of fiber-reinforced super workable concrete (FR-SWC). A comparative analysis of the influence of fiber combinations on the flexural

Conventional alkali-activated slag materials apply strong industrial alkalis with high cost and potential corrosion risk. Alternatively, this study utilized industrial solid waste phosphogypsum, soda residue, and calcium carbide slag to construct a salt-alkali synergistic activated system. A new salt-alkali synergistic activation effect was formed by the SO42− introduced by PG together with the Cl−

Fire is detrimental to skyscrapers. Lightweight high-performance concrete (L-HPC) developed by combining lightweight microspheres and ultra-high-performance concrete binder is promising for future mega infrastructure projects. This study investigates the fire resistance of lightweight high-performance cementitious composites developed using hollow ceramic microspheres (HCMs) and hollow glass microspheres

The layer interface, which is vital for the performance and longevity of 3D printed cement-based materials (3DPCM), is very sensitive to the environmental conditions because of the lack of formwork. Nevertheless, the current limited understanding of how temperature affects the layer interface has restricted the application of 3D printing in different construction scenarios. Here, we revealed the effects

This paper presents an electro-chemo-physical model for analyzing long-term chloride-induced reinforcement corrosion in concrete structures. The integration of electrochemical and thermodynamic analyses enables the proposed model to capture the influence of simultaneous reactions within concrete on the corrosion process. The model is validated against experiments, where the necessity of considering

The primary objective of this study was to develop cement composites with the ability to photocatalytically degrade contaminants and exhibit antimicrobial properties. To achieve this, titanium(IV) oxide was modified with carbon to create a photocatalyst active under both UV and visible light. The modified TiO2 was then combined with kraft lignin, a byproduct of paper production, resulting in functional

This study introduces a novel steel fiber arrangement, termed “bundled fibers,” where multiple high-strength steel wires are twisted into short, discontinuous fibers. The bond behavior of these bundled fibers in ultra-high performance concrete (UHPC) was evaluated through single-fiber pullout tests. Four variations of bundled fibers, consisting of two to five wires, were tested across three embedment

Assessing the impact of relative humidity (RH) on carbonation kinetics is crucial for the sustainable and high-strength advancement of CO2-activated Ca-bearing materials incorporating phase-controlling additives. This work focuses on the carbonation kinetics, mechanical properties, and microstructure evolution of carbonated wollastonite composites containing sodium tripolyphosphate (STPP) when exposed

This study investigated the aqueous carbonation mechanisms of three typical steel slags: ladle metallurgy furnace (LMF) slag containing high Al content, electric arc furnace (EAF) slag featuring high Si content and relatively low Al content, and ladle-arc fusion (LAF) slag with medium-Al content. It was found that the carbonation kinetics of the three slags were similar and followed the surface coverage

Alkali activation presents a promising method for the in situ resource utilization (ISRU) of lunar regolith. Enhancing the geopolymerization reactivity of lunar regolith simulant is key in minimizing alkali activator usage and improving raw material utilization. This study investigates the impact of thermal activation on precursor materials and the resultant geopolymers. Initially, the mineralogical

Steel reinforcement corrosion significantly reduces the durability and service life of concrete structures, particularly in chloride-rich environments such as marine and coastal areas. This study aims to reduce the corrosion rate using graphene oxide (GO) as a corrosion inhibitor. Two GO dosages (0.0005 and 0.005 wt%) were evaluated for their effectiveness in mitigating corrosion in reinforced concrete

Moisture diffusion influences the durability and long-term performance of concrete and whilst it predominantly occurs via the cement matrix and Interfacial Transition Zone, most existing models consider concrete to be homogeneous. This paper introduces a novel micro-meso model that employs random packing and Voronoi tessellation. Rayleigh-Ritz pore distribution and Brunauer-Skalny-Bodor models are

This study investigated the coupled effect of calcium leaching and chloride erosion on concrete subjected to hydraulic pressure by combining experiments and numerical simulations. Several tests including titration, pH, XRD, TG, MIP, and SEM-EDS were employed to analyze chloride concentration, pH value, solid phase compositions, and microstructure of concrete under hydraulic pressure. Concurrently,

Degradation of cementitious materials caused by sulfate attack poses a significantly challenge to their durability. Using nano-additives to enhance the mechanical and durability properties of cementitious materials is a promising solution; however, the impact of graphene oxide (GO) on the sulfate resistance is not yet fully understood. While efforts have been made to study the degradation mechanism

Reactive MgO cement (RMC) is a novel binder formed through the hydration and carbonation of MgO, but its low reactivity hinders its wider application. Preliminary research has suggested that citric acids can form compounds with Mg2+ that regulate these processes, but the mechanism is yet to be understood well. This study investigated the effects of citric acids on the fresh and hardened properties

This study compared the sulphate resistance of deionized water (DI)- and seawater (SW)-mixed cementitious materials based mainly on microstructural observations. The results show that, after a 450-day exposure to 50 g/L Na2SO4 solution, there was an increase in the mean chain length and polymerization degree of the remaining silicate chains in C-S-H gel for both DI- and SW-mixed pastes at a depth of

In this study, a two-step carbonation method is developed to control the formation of calcium carbonate (Cc) polymorphs on the surface of recycled hardened cement paste (RHCP) without the use of chemical additives. In the first step, RHCP undergoes semi-dry carbonation under controlled humidity conditions, followed by wet carbonation at various temperatures in the second step. The results show that

In this study, a number of different fibers - namely kenaf, jute, abaca, coir and sisal - were investigated as natural alternatives to polypropylene (PP) fibers for reducing plastic shrinkage cracking. The risk of plastic shrinkage cracking of mortars with water-to-cement ratio 0.5 containing either 0.6 or 0.9 kg/m3 of natural fibers was assessed according to the ASTM C1579-21 standard and compared

This study aims to investigate the effects of specimen thickness and fiber length on the tensile and cracking behaviors of ultra-high-performance fiber-reinforced concrete (UHPFRC). To this end, a uniaxial tensile test was conducted with three specimen thicknesses (30, 50, and 100 mm) and two fiber lengths (13 and 20 mm), and the fiber orientation, dispersion and specimen void were quantitatively evaluated

The layered deposition process of 3D concrete printing can lead to reduced mechanical properties at the interfaces between filaments. To address this limitation, external confinement devices, such as fiber-reinforced polymer (FRP) wrapping, have been proposed to enhance the strength of 3D-printed concrete concrete. Achieving this requires a solid understanding of the triaxial mechanical performance

The porous lightweight aggregates in concrete experience a process of water absorption and desorption. This study aims to improve the performance of water-sensitive low water/binder (w/b) systems by effectively utilizing these water regulations. The effects of expanded shale (ES) substitutions and saturation levels (dry, half saturation, and saturation) on the fresh and hardened properties of mixtures

The study aimed to elucidate the mechanism behind rheological modification due to CO2 mixing at the mixing and post-mixing stages from an electrochemical perspective. The results indicated that CO2 mixing reduced the flowability while increasing penetration resistance and static yield stress. The electrostatic attraction between particles with opposite surface charges and the bridging effect of calcium

Quantitative microstructure analysis of supplementary cementitious material (SCM) - blended paste through backscattered electron (BSE) imaging has long been intractable owing to the sophisticated micro phase distribution and overlapped greyscale histogram. This study explores the use of Convolutional Neural Network (CNN) based supervised semantic segmentation methods for quantifying phase assemblage

The preparation of foam concrete frequently encounters challenges such as foam collapse and stratification, which lead to a decline in material performance. Therefore, enhancing foam stability is paramount in the production of foam concrete. This study innovatively addresses this issue by investigating the use of waste fly ash particles (RFA) and modified fly ash (AMFA, BMFA, and CMFA) as foam stabilizers

Engineered Cementitious Composites (ECC) are ductile, strain-hardening cementitious composites with a tightly controlled crack opening profile. A significant concern in the development and application of ECC is its high carbon emissions associated with high cement content consumption. As an emerging green additive, biochar can significantly cut down on the carbon emission of concrete products. However

The hydration degrees of clinkers and ettringite stability in calcium sulfoaluminate (C S‾ A) cements in the presence of externally supplied dolomite were investigated in this study. The mineralogical and microstructural characteristics of C S‾ A cements containing different dosages of dolomite were characterized using X-ray diffractometry, Rietveld refinement-based quantification analysis, thermogravimetry

This study examines the potential of combining tailored binder formulations with engineered polypropylene (PP) fibers to develop a range of Fiber-Reinforced Cementitious (FRC) systems with enhanced ductility and strain-hardening properties, while encompassing sustainability and economic viability. The experimental investigation compares the surface microstructure of novel bicomponent PP fibers, produced

Efflorescence presents not only as a cosmetic concern but also as a structural issue, which impacts the performance of alkali-activated materials (AAMs). In this study, the mechanisms of efflorescence of alkali-activated slag (AAS) pastes are investigated. First, the efflorescence of AAS pastes with different alkali dosages (3 %, 5 % and 7 %), activator types (sodium hydroxide (NH) and sodium silicate

The use of supplementary cementitious materials (SCM) is projected to increase because they reduce the global warming potential of concrete. When cement is replaced with SCM, the flow of the mixture may change. The porosity of the paste may also change as the liquid-to-solid volumes change when mass replacement is used. This paper discusses the role of water absorption and the specific gravity of the

The study investigated the synergistic effects of combining superplasticizers with biopolymer-derived viscosity-modifying admixtures (VMAs) to enhance the performance of cement-based systems. Superplasticizers, including polycarboxylate ethers (PCE) and polynaphthalene sulfonates (PNS), were combined with VMAs derived from anionic (welan, tragacanth, and almond gums, and giant kelp extract) and non-ionic

The large-scale, environmentally friendly utilization of phosphogypsum (PG) remains a global challenge. PG cemented paste backfill (PCPB) is a promising method to manage PG, but using ordinary Portland cement as the binder has drawbacks such as high cost, low mechanical strength, and high fluoride leaching risk. This paper presents a multi-source solid waste-based PCPB (MPCPB) material that enhances

Accelerated carbonation presents a promising approach for enhancing the early strength of cement-based materials while simultaneously sequestering CO₂. This study examines the carbonation of γ-C₂S, β-C₂S, and C₃S compacts to identify the critical factors influencing strength development over extended curing periods. Analysis of the evolution of mechanical properties, microstructure, and phase assemblages

The weak interlayer adhesion caused by the layer-by-layer 3D printing (3DP) process and the incorporation of organic fiber in Engineered Cementitious Composites (ECC), detrimentally impacts the integrity of 3DP-ECC structures, particularly for large-scale structures requiring extended open time. To optimize the printing quality and extent the operation time, cellulose filaments (CF) were employed as

γ-C2S has been attracting much attention as the role of exclusive or primary binder to fabricate carbonated materials due to its high carbonation reactivity. However, the very limited hydration reactivity of γ-C2S makes it difficult in the production of casting-formed materials such as foam concrete, and this is exacerbated by the presence of bursting-prone foams in the mixture. Given the highly cementitious

During the past two decades, aerobic bacteria induced biomineralization has gained popularity for autonomous sealing of cracks in concrete structures due to its environmentally friendly characteristics of carbon retention. However, the mechanism of the biomineralization induced by aerobic bacteria for concrete crack sealing is still unclear due to the complex chemistry of cement matrix. Also, as the

3D concrete printing has attracted burgeoning interest in the construction industry for its ability to offer cost-effectiveness, architectural design flexibility, efficient use of energy and materials, as well as significant time savings in the construction process. However, conventional cement-geopolymer-based materials cannot be used directly for printing due to their lack of printability. This review

This paper reviews the formation and breakdown of passive film on the surface of reinforcement steel in alkali-activated materials (AAMs) considering the characteristics of reaction product and pore solution chemistry. The literature review shows that the pore solution of AAMs has higher concentrations of OH−, Na+, silica and aluminium compared to Portland cement (PC). This relatively high alkalinity

The load capacity, failure mode and durability of reinforced concrete members are strongly affected by the bond strength between the concrete and the reinforcement. This work presents a physics-based approach to improve the bond strength based on self-stressing effect. Combination of limestone calcined clay cement (LC3) and calcium sulphoaluminate cement (CSA) with different ratios was employed to

Vascular systems offer promising potential for enabling self-recovery in cementitious materials, but their construction in three dimensions presents significant challenges. Our group has developed an embedded printing strategy allowing for the freeform construction of 3D hollow vascular channels, overcoming previous limitations. However, concerns persist regarding the weakening of mechanical properties

Cellulose ethers (CE) are generally used as viscosity modifying admixtures in cement-based materials. However, previous investigations scarcely focus on the effect of CE on the calcium leaching behaviors of host materials. This work studied the calcium leaching behaviors in CE-containing cement pastes. The resistance to the calcium leaching was evaluated by the leaching depth, pH values and compressive

Chloride-induced corrosion of steel reinforcing bar (rebar) is the primary cause of deterioration in reinforced concrete structures, posing a significant infrastructure challenge. The chloride threshold level (CTL) of rebar, which represents the critical amount of chloride needed to initiate active corrosion, is crucial in corrosion and service life prediction models. However, substantial uncertainties

Developing novel, environmentally friendly, and efficient corrosion inhibitors is of great significance for improving the durability of marine concrete against chloride ion erosion. This paper aims to explore the potential of layered double hydroxides (LDHs) as nanocontainers, incorporating organic corrosion inhibitors between LDHs layers to synergistically enhance their effectiveness. In this study

This study considers the different engineering application environments for normal use and emergency repair of reinforced concrete structures. The natural passivation and chloride corrosion resistance of Inconel 625 in Ordinary Portland cement (OPC) and Calcium Sulfoaluminate cement (CSA) was first evaluated through electrochemical measurement and surface analysis techniques. OPC and CSA related to

This paper presents the mechanical properties of composite beams additively manufactured by 3D-printing of layers of mortar on top of custom-designed (also 3D-printed) steel plates, which served as external flexural reinforcement. The mechanical performance of the composite beams was evaluated using three-point bending test. The results were compared with the data obtained from two types of reference

Cement-based materials (CBM) in humid environments, influenced by their inherent defects and the presence of pore solution, exhibit poor electrical insulation performance. Low electrical resistivity of cement-based materials poses a threat to the safety of resilient infrastructures, shortens the lifespan of materials, and increases the costs of maintenance and repair. In this work, we first elucidate

Seawater cement slurry (SCS) is a commonly used binder in offshore deep cement mixing (DCM) construction. Seawater cement slurries are usually prepared before they are grouted into the seabed and mixed with marine clay. The aim of this study is to explore the feasibility of applying carbonation technology to fabricate SCS suitable for offshore DCM while achieving carbon sequestration and obtaining

This paper introduces a theoretical model for forecasting fiber orientation in 3D-printed ultra-high-performance concrete (3DP-UHPC). Initially, the dynamic evolution process of fiber alignment in 3DP-UHPC was characterized using X-ray computed tomography (X-CT) and image analysis. The results indicated that fiber alignment during extrusion process was primarily constrained by the rigid boundary of

The design of cementitious mixtures incorporating mine tailings as fine aggregates is a multi-objective optimization (MOO) problem, in which both the uniaxial compressive strength (UCS) and cost of the mixtures need to be considered simultaneously. Given that data-driven methods have shown promising results when solving similar MOO problems, this study developed an extreme gradient boosting regressor

Glycol-based components are commonly used as grinding agents in ordinary Portland cement (OPC). However, their effects on the grindability and hydration mechanism have not been fully understood. In this study, the effects of mono-ethylene glycol (MEG) of various concentrations (0, 0.025, and 0.05 %) on OPC grinding characteristics as well as hydration reaction were examined. The use of MEG improved

Pozzolans rich in silica and alumina react with lime to form cementing compounds and are incorporated into portland cement as supplementary cementitious materials (SCMs). However, pozzolanic reactions progress slower than portland cement hydration, limiting their use in modern construction due to insufficient early-age strength. Hence, alternative SCMs that enable faster pozzolanic reactions are necessary