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Nanoscale graphene has demonstrated effectiveness in self-sensing cement composites and energy harvesting in buildings. However, the widespread application of graphene reinforced cement composites (GRCCs) in energy conversion is hindered by their low thermoelectric conversion efficiency. To address this limitation, multiphase cement composites with high Seebeck coefficient and low thermal conductivity are designed by using Cu2Se and ZnO. The increase in carrier mobility and enhanced phonon scattering lead to an order of magnitude improvement in the figure of merit (ZT) compared to GRCCs without incorporating Cu2Se/ZnO. A hybrid micromechanical model (HMM) based on effective medium theory and the Mori–Tanaka method is developed for predicting the electrical and thermal conductivity of the multiphase cement composites, which can be used to evaluate the thermoelectric performances of the composites. The combined experiments and modeling aim to provide guidelines for developing high-performance GRCCs with improved thermoelectric properties, potentially expanding their application in energy conversion technologies. [ABSTRACT FROM AUTHOR]

Ordinary cement mortar is commonly used in building engineering due to its high strength, affordability, and easy access to raw materials. However, it suffers from high shrinkage and poor impermeability, which result in reduced building service life and significant carbon dioxide emissions during production. Polymer additives have been found to enhance the mechanical properties of cement mortar, leading to increased interest in polymer cement mortar by researchers. This study collected and analyzed 420 papers published between 1995 and 2023 in the field of polymer cement mortar. The analysis included publication trends, author cooperation networks, national cooperation networks, published journals, co-citation of references, and keywords. The findings reveal a rapid publication growth from 2018 to 2023, with China making the most significant contribution in this field. Among the scholars, Ru Wang has published the highest number of articles in the field of polymer cement mortar, while Ohama's papers have been cited the most. The journal with the most articles is Construction and Building Materials. Research in polymer cement mortar focuses on mechanical properties, performance, hydration process, microstructure, and other related aspects. The reinforcement effect of polymer-modified cement mortar on reinforced concrete and applying superabsorbent polymer-modified cement mortar and polymer fiber in cement mortar have emerged as recent research frontiers. This study can help scholars quickly identify high-quality references and research frontiers in the field of polymer cement mortar while also providing research directions and ideas. [ABSTRACT FROM AUTHOR]

The prediction of electrical resistivity of graphene oxide (GO) reinforced cement composites (GORCCs) is essential to promote the application of the composites in civil engineering. Traditional experiments find it challenging to capture the effect of various features on the electrical resistivity of the GORCCs. In this work, machine learning (ML) techniques are employed to explore the complex nonlinear relationships between different influencing factors and the electrical resistivity of the GORCCs. A total of 171 datasets are utilized for training and testing the ML models. It is demonstrated that the applied ML models are effective and efficient. Apart from the water/cement ratio, correlation analysis shows that the electrical resistivity of the GORCCs is highly dependent on the specimen size and measurement method. Feature importance analysis shows that the dispersion of GO has a significant influence on the electrical resistivity. The extreme gradient boosting (XGB) model and the artificial neural network (ANN) model with 3 hidden layers are proven to have better predictions, as evidenced by higher R2 and lower root mean square error (RMSE). This work is envisioned to provide an effective and efficient way to identify the complex relationship between the material properties of the GORCCs and the various influencing factors. [ABSTRACT FROM AUTHOR]

Concrete columns are the backbone of any major structure, and their strengthening, repair, and retrofit have always drawn special research attention. One of the techniques for strengthening and improving the ductility of concrete columns has been the application of carbon fiber–reinforced polymer (CFRP) materials. A total of 43 columns of different configurations were experimentally investigated to evaluate the uniaxial compressive behavior of composite columns. Experimental and international code–recommended load-carrying capacities, stress–strain relations, axial stiffness, ductility factor, and failure modes were examined in the study. When fully wrapped, the strength of both plain cement concrete and reinforced cement concrete columns improved by 21% each with reference to the unwrapped columns. In addition to providing the advantages of external confinement to the columns, full wrapping contributed to a strength increment of 21%, which compared well with the steel reinforcement contribution to a strength increment of 28% to 39%. The partial wrapping technique was found to be an economical alternative to the full wrapping technique, with strength enhancements of 6% to 12% in the case of both plain cement concrete and reinforced cement concrete partially wrapped columns. Two regression models for the load-carrying capacity for columns with and without wraps were developed with four key performance parameters: percentage steel reinforcement, percentage concrete, percentage carbon fiber–reinforced polymer wrap, and the weight of the specimen. The formulated models were validated and found to be robust and consistent with the results. [ABSTRACT FROM AUTHOR]

The aim of this study is twofold. First, to assess the effect of the sonication process on the optimal dispersion of GO sheets for nanostructural reinforcement of cement pastes, as there is currently no clear criterion on this effect in the literature. For this purpose, in the first stage, the GO content in distilled water was fixed at 0.03% by weight, and the sheets were dispersed using different levels of ultrasonic energy, ranging from 0 J/mL to 2582 J/mL. In the second stage, to analyze the modification of pore structure due to the addition of GO sheets in different ratios (0–0.06% by weight) and its relationship with the mechanical and fracture properties of reinforced cement pastes. According to the results, it has been determined that the incorporation of GO sheets into the matrix alters the mechanical and fracture behavior, varying depending on matrix pore size and GO particle size. The addition of GO leads to a reduction in the average size of macropores (greater than 8 µm) of 13% for a dosage of 0.45% in weight and micropores (between 8 and 0.5 µm) in a 64% for the same composition with non-sonicated GO, although the total volume of pores in these ranges only decreased slightly. This reduction is more pronounced when the GO has not been sonicated and has larger particle size. Sonicated GO primarily modifies the range of capillary pores (<0.5 µm). The addition of GO with the highest degree of dispersion (465 nm) did not show significant improvements in compressive strength or Young's modulus, as the cement used contains a significant volume of macropores that are not substantially reduced in any composition. Adding 0.030% ultrasonicated GO achieved a 7.8% increase in fracture energy, while an addition of 0.045% resulted in a 13.3% decrease in characteristic length, primarily due to the effect of capillary and micropores. [ABSTRACT FROM AUTHOR]

An assessment of radioactivity concentration of reinforced cement concrete types of house was conducted in the valley region of Manipur, India. The average radioactivity concentration of 226Ra, 232Th, and 40K of portland cements are 39 (range: 32–52) Bqkg−1, 36 (range: 22–62) Bqkg−1, and 1812 (1254–2424) Bqkg−1; for concrete are 36 (range: 26–45) Bqkg−1, 65 (range: 45–86) Bqkg−1, and 660 (639–681) Bqkg−1; for sand are 45 (30–61) Bqkg−1, 114 (range: 55–212) Bqkg−1, and 1859 (range: 1413–2232) Bqkg−1; and for bricks are 30 (range: 24–37) Bqkg−1, 148 (range:79–184) Bqkg−1, and 1444 (range: 1093–2103) Bqkg−1, respectively. The annual effective dose was observed with an average value of 1.9 (range: 0.9–3.3) mSvy−1. However, gamma index was observed with an average value of 1.1 (range: 0.5–2.0). [ABSTRACT FROM AUTHOR]

This innovation aims to provide a Simple House (SH) Type 24 m2 (T-24) floor area made from PVC pipes and Glass-Fiber Reinforced Cement (GRC) boards. The simple house-building structure in this invention consists of PVC pipes and GRC boards which are arranged based on simple building designs in Indonesia. PVC pipes as components of the building space frame and roof are reinforced with reinforced concrete mixed and PVC pipe connections. The potential for users of simple houses for low-income people (MBR) is very large in Indonesia. With a shortage of one million houses per year, the PUPR Ministry is only able to meet 30% or around 400,000 units per year of people's housing needs. The benefit and advantage of innovation is that space frame building construction consisting of floor beams, columns, and ring beams made from PVC pipes is easy to do using relatively simple craftsman equipment. The T-24 simple house innovation is a building that is easy to work on because this building uses materials that can be easily found in various regions in Indonesia, namely PVC pipe materials and GRC boards. In summary, the T-24 simple house prototype has the following innovations: 1) cement brick foundation, 2) construction of floor beams, columns, and ring blocks using PVC pipes and concrete mix without splitting, 3) main roof material structure (horses and battens) made from PVC pipes, 4) SH T-24 roof covers and walls made from GRC boards, 5) Building features such as doors and windows use a combination GRC boards and glass materials. [ABSTRACT FROM AUTHOR]

In the pursuit of creating more sustainable and resilient structures, the exploration of construction materials and strengthening methodologies is imperative. Traditional methods of relying on steel for strengthening proved to be uneconomical and unsustainable, prompting the investigation of innovative composites. Fiber-reinforced polymers (FRPs), known for their lightweight and high-strength properties, gained prominence among structural engineers in the 1980s. This period saw the development of novel approaches, such as near-surface mounted and externally bonded reinforcement, for strengthening of concrete structures using FRPs. In recent decades, additional methods, including surface curvilinearization and external prestressing, have been discovered, demonstrating significant additional benefits. While these techniques have shown the enhanced performance, their full potential remains untapped. This article presents a comprehensive review of current approaches employed in the fortification of reinforced cement concrete structures using FRPs. It concludes by identifying key areas that warrant in-depth research to establish a sustainable methodology for structural strengthening, positioning FRPs as an effective replacement for conventional retrofitting materials. This review aims to contribute to the ongoing discourse on modern structural strengthening strategies, highlight the properties of FRPs, and propose avenues for future research in this dynamic field. [ABSTRACT FROM AUTHOR]

Green roofing technologies have been developed and implemented worldwide as they bring with them thermal, hydrological, and environmental benefits, especially in urbanized areas. Many studies have been conducted to investigate the thermal performance of green roofs over reinforced cement concrete (RCC) structural bases but there is a lacuna of experimental evaluation of the thermal performance of green roofs on sloping galvanized iron (GI) sheet truss type roof structures. In this paper, the thermal performance of a retrofitted extensive green roof is quantified; this is challenging in subtropical climates because of extreme seasonal and diurnal variations. The thermal performance of the green roof system was assessed using a life-size experiment setup followed by a whole-building simulation using Design Builder, which runs on the EnergyPlus simulation engine. Two prototype roofs were analyzed and the performance of the retrofitted extensive green roof was compared with that of a conventional RCC roof solution. To validate the results, two prototype buildings were constructed at a university campus and their thermal and energy performance analyzed for two observation periods, one during a typical summer week and the other during a typical winter week. The extensive retrofitted green roof displayed enhanced thermal and energy performance at a nominal additional cost. The findings of this study can be deployed in the development of a retrofitted extensive green roof module for sloped GI sheet roofs for better thermal performance, and hence reduced energy loads, and meet the sustainable development goals. [ABSTRACT FROM AUTHOR]

An insulated building-integrated photovoltaic (PV) roof prototype is designed, developed, and experimentally monitored for the composite climatic conditions in the current work. The prototype is monitored based on hourly indoor room temperature, relative humidity, discomfort index, decrement factor time lag, and power generation. To validate the results, a heat conduction equation was developed and simulated considering actual lower income group (LIG) building size and materials. Second-order polynomial equations were derived from simulation results to optimize insulation thickness. Additionally, the economic analysis of the insulated building-integrated Photovoltaic (BIPV) roof was analyzed and compared to the reinforced concrete cement (RCC) roof. The results reveal that insulated BIPV roofs outperform the RCC roof, reducing indoor temperatures by 3.34 ℃ to 1.37 ℃ within an optimum thickness range of 0.0838–0.1056 m. A time lag of 1 h and a significant reduction in decrement factor up to 0.29 are achieved. The average discomfort index of the proposed roof during sunshine hours was found to be between 23 and 26.5. The insulated BIPV roofs with levelized cost of electricity (LCOE) of the 3.38 Rs/kWh gave a payback period of 6.32 years and a higher internal rate of return of 29.4 compared to RCC roof. The current study increases the feasibility of PV modules to be used as building material. [ABSTRACT FROM AUTHOR]

Objective. Development of compositions of vermiculite concrete and fibro vermiculite concrete with volcanic pumice. Investigation of the construction and technical properties of the developed compositions of vermiculite concrete and fibrovermiculite concrete with volcanic pumice under the influence of elevated temperatures.Method. Methods of increasing the fire resistance of reinforced concrete structures are considered. The research is aimed at the development of vermiculite concrete and fibro vermiculite concrete with volcanic pumice for fire protection of building structures and the manufacture of heat-resistant products and structures. To reduce the cost of vermiculite concrete, its partial replacement with volcanic pumice is proposed. For the study of vermiculite concrete with volcanic pumice reinforced with basalt fiber, a rotatable plan of the second order of the regular hexagon type was used.Result. Replacing a part of an expensive aggregate (expanded vermiculite) with pumice leads to a slight increase in the average density of the composite, while the bending and compressive strength increases. In addition, the heat-resistant properties of vermiculite concrete with pumice are increased. This is due to the fact that volcanic pumice, being a hydraulically active additive, is able to react hydration with cement components, eliminating the harmful effect of secondary hydration of free calcium oxide. The influence of the heating temperature on the change in the construction and technical properties of vermiculite concrete and fibrovermiculic concrete, including with the addition of pumice, has been studied. It was found that dispersed reinforcement with basalt fibers reduces shrinkage deformations, when heated to t = 800, the shrinkage decreases from 0.7 to 0.5% compared to the original concrete matrix.Conclusion. The dependence "compressive strength = f (average concrete density)" significantly depends on the presence and ratio of pumice in the composition of vermiculite concrete, while an increase in the holding temperature to 600 oC or 800 oC leads to a decrease in the compressive strength from 15 to 25%, and the main decrease occurs when heated to 600 oC, further the increase in temperature has a negligible effect. The dependence of the bending strength on the compressive strength is generally maintained regardless of the heating temperature, and the heating of concrete does not reduce the relative bending strength, i.e. the ratio of bending strength / compressive strength is not reduced. Dispersed fiber reinforcement increases the relative bending strength by about 70% regardless of the heating temperature.

This research is aimed at obtaining boron-containing nanotubular chrysotile fibers with increased neutron absorption capacity. The possibility of using an organosilicon modifier based on tetraethoxysilane to increase the hydrothermal stability of chrysotile, as well as the strength of nanoreinforced composites based on a cement binder is considered. The mechanisms for the synthesis of heat-resistant nanotubular fibers of the composition Mg6(OH)8SiB4O10, which have a chrysotile structure, have been established. To increase the hydrothermal stability of chrysotile, crystalline hydrate phases were localized inside nanotubes using amorphous silica formed as a result of hydrolysis of silicon alkoxide under hydrothermal conditions in an alkaline environment. The modification of chrysotile via amorphous silica increases its hydrothermal stability by 97 °C. It is shown that the introduction of an organosilicon modifier based on tetraethoxysilane into the composition of Portland cement composite material leads to an increase in the structural strength and density of the composite due to the activation of silicate formation processes in the cement matrix, especially under hydrothermal conditions. The experiments showed that the strength of silicon alkoxide-modified samples of composite material increased by 34%. [ABSTRACT FROM AUTHOR]

Fires being a Low-Probability High-Consequence problem, can have a big impact on the structures due to their occurrence; irrespective of the construction materials. Even, the damage might lead to structural collapse. Such failures have warned to check the impact of fire on structural elements, which is frequently overlooked in popular design guidelines. Warehouses are used for the storage of different types of commodities; however, the vulnerability of these structures during fire event depends on the storage materials and other factors. Such a warehouse with steel roof trusses supported over Reinforced Cement Concrete (RCC) frame, located at Kolkata, suffered one of such severe fire-induced damage; and the roof truss system along with some portions of the brick masonry walls got totally collapsed. The information about the structure including its design data is presented along with the site observations after the fire incident, and the results of various Non-Destructive Tests (NDTs) performed over RCC frame elements. A severe fire of 8-hour duration led to a huge increase in temperature, which is considered to be the main reason of the progressive collapse of the entire warehouse structure. To better understand the failure of members due to temperature load, the present study aims to analyse a numerical model of the damaged structure in the Finite Element (FE) Framework. The roof truss, RCC frames and brick masonry walls are modelled; and temperature load is applied along with self-weight load to check the effect of incremental temperature on various structural responses of the warehouse. The temperature-dependent material properties are considered in the analyses; as applicable. Results have shown that there is a significant effect of temperature load, which gets worse with increasing temperature. The connection between roof truss and columns also contributes to the extent of damage in the truss supported over RCC frames; as evident from the numerical analysis. The present study seems to present a clear view about the fire-induced structural collapse of a real-life warehouse structure. [ABSTRACT FROM AUTHOR]

Global warming triggered efforts on sustainable materials in any area of production. Thus, the construction materials were also at the edge of a sharp change to achieve less harm to the environment by reducing the carbon print. Consequently, researchers have been trying to replace the cement from the mixtures of reinforced concrete as cement production causes large amounts of carbon dioxide emissions. Alkali‐activated binders are proved to be versatile alternatives to cementitious binders; however, accurate mathematical models to predict the capacities of these structural elements are limited in number. Therefore, in this study, a new stress–strain model has been developed to estimate the flexural capacity of geopolymer structural elements originated from construction and demolition waste. The study was initiated by formulating a novel stress–strain model applicable for defining the compressive behavior of geopolymer concrete. The formulation was based on recent experimental findings on flexural behavior of geopolymer beam specimens. Then, the performance of the proposed stress–strain model in estimating the ultimate moment capacities was investigated by using 36 bending tests from the literature. The results showed that the proposed model had very little deviations and enhanced accuracy compared with the literature available estimation method recommended by the ACI318. In addition, a soft database composed of 50 different beam specimens with varying mechanical properties and reinforcement patterns was formed. Numerical models corresponding to all possible combinations of each parameter were generated, and their load capacities were determined. After that, the estimation performances of the proposed method and the stress–strain models from the literature, and also the ACI318 procedure were examined. The conclusion of this check also yielded promising results with an absolute mean percentage error of 5.13% regardless of the mode of failures. [ABSTRACT FROM AUTHOR]

Computational approaches could provide a viable and cost-effective alternative to expensive experiments for accurately evaluating the nonlinear constitutive behavior of cementitious nanocomposite materials. In the present study, the mechanical properties of cement paste reinforced with multi-wall carbon nanotubes (MWCNTs) are examined experimentally and numerically. A multiscale computational approach is adopted in order to verify the experimental results. For this scope, a random sequential adsorption algorithm was developed to generate non-overlapping matrix-inclusion three-dimensional (3D) representative volume elements (RVEs), considering the inclusions as straight elements. Nonlinear finite element analyses (FEA) were performed, and the homogenized elastic and inelastic mechanical properties were computed. The use of a multiscale computational approach to accurately evaluate the nonlinear constitutive behavior of cementitious materials has rarely been explored before. For this purpose, the RVEs were analyzed both in pure tension and compression. Young's modulus as well compressive and tensile strength results were compared and eventually matched the experimental values. Moreover, the effect of MWCNTs on the nonlinear stress–strain behavior of reinforced cement paste was noted. Subsequently, three-point bending tests were conducted, and the stress–strain behavior was verified with FEA in the macro scale. The numerical modeling reveals a positive correlation between the concentration of MWCNTs and improved mechanical properties, assuming ideal dispersion. However, it also highlights the impact of practical limitations, such as imperfect dispersion and potential defects, which can deteriorate the mechanical properties that are observed in the experimental results. Among the different cases studied, that with a 0.1 wt% MWCNTs/CP composite demonstrated the closest agreement between the numerical model and the experimental measurements. The numerical model achieved the best accuracy in estimating the Young's modulus (underestimation of 13%), compressive strength (overestimation of 1%), and tensile strength (underestimation of 6%) compared to other cases. Overall, these numerical findings contribute significantly to understanding the mechanical behavior of the nanocomposite material and offer valuable guidance for optimizing cement-based composites for engineering applications. [ABSTRACT FROM AUTHOR]

The use of natural materials, such as natural fibres, in the construction industry is becoming more frequent. The source of natural fibres should be sought in local plants, such as Spanish Broom in the Mediterranean area. The fibre treatment process was carried out in 8 different ways with alkali 4%, 5%, 6%, 8%, 10% and 15% NaOH solution, and 5% NaOH and 2% Na2SO3 mixture solution and seawater. The fibres were tested for tensile strength. No relationship was established between the concentration of the solution and the tensile strength of the fibres. The influence of the reuse of treatment solution on fibre quality was monitored by X-ray diffraction (XRD), ATR-FTIR, and TG/DTG analysis. Fibres with lengths of 1, 2, and 3 cm were added to cement mortar specimens in amounts of 0.5 and 1 vol%. The flexural and compressive strengths were tested on mortar specimens after 28 days. For fibres 1 and 3 cm long, 0.5% natural fibre content gives higher strength results: about 9% for flexural strength and 13.5% and 11.7% for compressive strength in regard to mortar reinforced with fibres of the same length but with a proportion of 1%. For mortar reinforced with fibre 2 cm long, better results are achieved with 1% fibre content, namely 9% higher flexural strength and 11.2% higher compressive strength compared to mortars with 0.5% fibre content. SEM/EDS analysis showed that the fibres are integrated into the cement matrix but that there is no strong interaction with the binder. For examination and 3D visualisation of mortar specimens, a medical device MSCT (Multi-slice Computed Tomography) was also used. For three consecutive years of Spanish Broom harvesting, an analysis of meteorological conditions and the results of the mechanical strength of reinforced mortars is given. For the examined years, the meteorological conditions did not affect the obtained results. Additional knowledge about the Spanish Broom fibres can introduce this plant to the application of new sustainable building materials. [ABSTRACT FROM AUTHOR]

Ceramic waste generated by demolition and manufacturing processes is a kind of widely discharged solid waste; its sustainable use can reduce resource extraction, energy consumption, and carbon emissions, thereby reducing the environmental impact. In this study, ceramic powder and ceramic sand were prepared using waste ceramic wall tiles. By using three water-to-binder ratios of 0.30, 0.32, and 0.34, five ceramic powder replacement rates of 10% to 50%, and completely using ceramic sand as the fine aggregate, specimens with large differences in mechanical properties were prepared. Firstly, the compressive strength was investigated. On this basis, hybrid fibers were employed to strengthen the new matrix material, and its bending resistance was experimentally studied. It was found that the incorporation of ceramic powder reduced the compressive strength of the matrix. The water-binder ratio significantly affects compressive strength at an early age. The effect of PVA fiber on improving the ductility of the new composite is distinct. Increasing the amount of steel fiber can effectively enhance the bending bearing capacity.With a ceramic powder dosage of 50%, the new composite has shown ductile failure characteristics, even with low total fiber content. The bending properties of this new composite material, which makes extensive use of ceramic waste, are well adjustable. The bearing capacity and ductility balance can be achieved with the steel fiber content of 1% and the PVA fiber content of 1.2% to 1.50%. [ABSTRACT FROM AUTHOR]

Concrete usually possesses advantages of high compressive strength but weaknesses of low tensile strength originating from the intrinsic brittleness of cement hydrates. Here we propose a method of in situ copolymerization of monomers that use acrylic acid (AA) and acrylamide (AM) to restrain the brittleness of cement hydrates by in situ copolymerization during cement hydration and to enhance the mechanical strength of the cement matrix. Cement pastes with reinforced flexural strength and compressive strength can be obtained by modulating the fraction of AA-AM copolymer. With the polymerization reaction, a polymer skeleton was constructed in the cement matrix, followed by crosslinking with cement hydrates by the coordination between metal ions (Ca2+ and Al3+) and carboxy groups, enhancing the flexural strength and toughness of cement pastes. Our work offers a straightforward method to reduce the intrinsic brittleness of cement hydrates, providing a facile access to cementitious materials with improved flexural performance. [ABSTRACT FROM AUTHOR]

In recent years, cases of the improper utilization of steel furnace slag have been widely reported, resulting in a crisis of nowhere for recycled resources such as inorganic slag. The misplacement of resource materials that originally had sustainable-use value not only has a great impact on society and the environment but also greatly reduces industrial competitiveness. To solve the dilemma of steel furnace-slag reuse, it is critical to find solutions to the stabilization of steelmaking slag under the innovative thinking of the circular economy. In addition to enhancing the reuse value of recycled resources, the balance between economic development and environmental impact is also crucial. The high-performance building material could provide a solution based on a high-value market. With the development of society and the increasing requirements for quality of life, the requirements for the soundproof and fireproof performance of lightweight decorative panels common in cities have gradually become popular. Therefore, the high performance of fire retardant and soundproofing could be the main development focus of high-value building materials to ensure circular economic feasibility. This study continues the research results of the application of inorganic re-cycled engineering materials in recent years, and the application of electric-arc furnace (EAF)-reducing slag to the development of base materials for reinforced cement boards, in order to complete the development of high-value panels with fireproof and sound-insulation properties in line with the engineering characteristics of the boards. The research results showed the optimization of the proportions of the cement boards with EAF-reducing slag as a raw material. The proportions of EAF-reducing slag to fly ash at ratios of 70:30 and 60:40 all met the requirements of ISO 5660-1 Class I flame resistance; the sound transmission loss in the overall frequency band can reach more than 30 dB, which is higher by 3–8 dB or more than the same board with similar specifications (such as 12 mm gypsum board) in the present building-materials market The products could be developed into building partitions and ceiling decoration boards with high performance in terms of fire retardant and soundproofing values, and also reduce the use of natural raw materials by more than 35%. The results of this study could meet environmental compatibility targets and contribute towards greener buildings. This model of circular economics would achieve energy reduction, emissions reductions, and be environmentally friendly. [ABSTRACT FROM AUTHOR]

Objective. Development of compositions of fire-retardant vermiculite-concrete composites for reinforced cement structures. Investigation of the properties of fire-retardant vermiculite-concrete composite and fine-grained concrete for two-layer reinforced cement structures.Method. Methods for increasing the fire resistance of reinforced concrete structures are considered. Research is focused on the development of fire-retardant composites using expanded vermiculite and volcanic ash. To improve the physical and mechanical properties of the fire-retardant composite, a mixture of Portland cement, gypsum, lime, basalt fiber, saponified wood resin, volcanic ash and expanded vermiculite has been developed. For the study of vermiculite concretes reinforced with basalt fiber, a second-order rotatable plan of the regular hexagon type was used.Result. Fiber-vermiculite concretes are proposed, which have improved fire-retardant properties compared to known compositions. This is due to the better preservation of the fiber-vermiculite-concrete layer when heated as a result of fiber reinforcement. Also, thanks to the addition of SDO, the fire-retardant properties of the composite increase due to the additional porosity of the fiber-vermiculite-concrete. The parameters of the "stress-strain" diagram of a vermiculite-concrete composite and fine-grained concrete have been obtained.Conclusion. Vermiculite concretes with an average density of 480-560 kg/m3 have the best fire-retardant properties. The developed two-layer reinforced cement structures have high fire resistance.

This paper discusses the challenges in characterizing electromagnetic (EM) waves propagating through inhomogeneous media, such as reinforced cement concrete and hot mix asphalt. Understanding the EM properties of materials, including their dielectric constant, conductivity, and magnetic permeability, is crucial to analyzing the behavior of these waves. The focus of this study is to develop a numerical model for EM antennas using the finite difference time domain (FDTD) method, and to gain a deeper understanding of various EM wave phenomena. Additionally, we verify the accuracy of our model by comparing its results with experimental data. We analyze several antenna models with different materials, including the absorber, high-density polyethylene and perfect electrical conductors, to obtain an analytical signal response that is verified against the experimental response. Furthermore, we model the inhomogeneous mixture of randomly distributed aggregates and voids within a medium. We verify the practicality and reliability of our inhomogeneous models using experimental radar responses on an inhomogeneous medium. [ABSTRACT FROM AUTHOR]

This paper deals with an experimental study of the flexural behavior of sustainable reinforced cement concrete (RCC) beams with a smart mortar layer attached to the concrete mixture. In total, nine RCC beams were cast and tested. Two types of reinforced concrete beams were cast, and three different beams of sizes 1000 × 150 × 200 mm and six different beams of sizes 1500 × 100 × 250 mm were considered. The flexural behavior of these RCC beams was studied in detail. The electrical resistivity of these beams was also calculated, which was derived from the smart mortar layer. Research on the application of smart mortars within structural members is limited. The experimental results showed that the smart mortar layer could sense the damage in the RCC beams and infer the damage through the electrical measurement values, making the beam more sustainable. It was also observed that the relationship between the load and the fractional change in electrical resistance was linear. The fractional change in electrical resistivity was found to steadily increase with the increase in initial loading. A significant decrease in the fractional change in electrical resistivity was seen as the load approached failure. When a layer of mortar with brass fiber was added to the mortar paste, the ultimate load at failure was observed and compared with the reference beam specimen using Araldite paste. Compared to the hybrid brass-carbon fiber-added mortar layer, the brass fiber-added mortar layer increased the fractional change in the electrical resistivity values by 14–18%. Similarly, the ultimate load at failure was increased by 3–8% in the brass fiber-added mortar layer when compared to the hybrid brass-carbon fiber-added mortar layer. Failure of the beam was indicated by a sudden drop in the fractional change in electrical resistivity values. [ABSTRACT FROM AUTHOR]

Seismic resilience is of paramount importance for the design and construction of structures in earthquake-prone regions. This study aims to provide a comprehensive analysis of the seismic performance of steel-concrete composite and Reinforced Cement Concrete (RCC) structures under dynamic loading, facilitating a comparative assessment of their respective behaviors. The behavior of cement-concrete composite structures, emphasizing the interactions between steel and concrete components, their energy dissipation mechanisms, and their contributions to seismic resistance are explored. This review contributes to the advancement of seismic design guidelines, aiding architects, engineers, and policymakers in making informed decisions regarding safer and more resilient structures. [ABSTRACT FROM AUTHOR]

To improve the tensile, flexural, and ductility properties of geopolymer composites, amorphous metallic fibres (AMF) are used to reinforce these composites, and the behavior of these composites at elevated temperatures has been assessed in this study. Four types of composites, i.e., cement, reinforced cement, geopolymer, and reinforced geopolymer composites have been prepared. The composites have been reinforced using AMF with a fibre volume fraction of 0.75%. The composites have been assessed for change in mass loss, cracking, compressive strength, and flexural strength at four elevated temperatures of 200 °C, 400 °C, 600 °C, and 800 °C, and conclusions have been drawn concerning these composites. The results have shown that an increase in temperature has an adverse effect on these composites, and geopolymer composites exhibit higher performance than their counterpart cement composites at elevated temperatures. The mass loss and surface cracking were significantly lower in geopolymer composites, and the fibre reinforcement had a negligible effect on mass loss. Also, the residual compressive and flexural strength of reinforced geopolymer composites was significantly higher than that of the reinforced cement composites. In addition, scanning electron microscopic images also showed that even at higher temperatures, the geopolymer matrix is present on the AMF fibre, which results in higher residual strength than the cement composites in which a negligible amount of matrix is present on the fibres. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the effects of yarn intermingling parameters on the bending properties of cement-based composites reinforced with polypropylene fabric treated under cold plasma. In this research, FDY (Fully drawn yarn) polypropylene yarn by three types of Heberlein intermingle jet inserts (P212, P412, S16), was subjected to entanglement process. Then, meshes were woven in plain weave design. The meshes were subjected to cold plasma jet treatment with argon and nitrogen at different exposure time. The fabric surface roughness was studied by friction test. Reinforced cement composite beams were made which after 28 days of storage in water, were subjected to 4-point bending test. The results show that the jet insert change with changing the degree of entanglement affects the toughness and bending properties. The max toughness is related to the plasma untreated fabric reinforced cement composite containing raw yarn (FDY) which is equal to 2388.875 (N.mm). Also, the max bending force is related to the fabric-reinforced sample consisting of interlaced yarn by P412 jet insert and plasma untreated fabric (1249.567 (N)). [ABSTRACT FROM AUTHOR]

Recently, the reinforced cement concrete (RCC) frame has been one of the most commonly used structural systems for buildings in the high seismic region due to its inherent earthquake-resistant property. However, there is still a deficiency in understanding the RCC building structural system dynamic behaviour during significant earthquakes. A 1/4th scaled RCC framed building structure has been tested on the shake table in the present study. The response in terms of engineering parameters like natural time period, damping, story acceleration, and damage pattern have been reported. The 1940 EL-Centro (NS component) time history has been used for the study. The failure patterns were observed within the column-beam joints. The difference between the input signal and the output signal has been noted and found to be in good agreement with each other. [ABSTRACT FROM AUTHOR]

Cement, one of the main components of concrete, poses environmental risks, accounting for 7% of total global carbon emissions. To alleviate the environmental hazards related to cement manufacturing, supplementary cementitious materials (SCM) are employed to reduce the usage of cement in concrete. One SCM used is copper slag (CS). In this study, a life cycle assessment (LCA) is conducted by investigating the environmental impacts of concrete replacing different percentage of cement with CS. As a case study, the LCA was performed for low-rise and mid-rise structures designed with varying concrete strengths, and a cost analysis was performed for these structures when replacing different percentages of cement with CS. Based on the results, the usage of CS was established as being beneficial to the impact categories ADP (Abiotic Depletion Potential (Fossil)) and GWP (Global Warming Potential), but exerted damaging effects on ADP (Abiotic Depletion Potential) and HTP (Human Toxicity Potential). On the basis of the cost analysis, the use of CS as a partial cement replacement was found to reduce building costs by a maximum of 1.4%, which is statistically significant. When evaluating the risk in comparison to the benefit of using CS in buildings, it was found that the negative environmental influence outweighed the favorable influence and cost savings resulting from the use of CS as a cement alternative. However, when only considering GWP, which is the standard procedure for environmental assessment in buildings, the use of CS as a partial cement substitute in buildings was regarded as being beneficial, yielding a 12.80% reduction in carbon emissions. [ABSTRACT FROM AUTHOR]

The interaction of reinforcement bars with concrete determines the structural behavior and bond performance (bond strength) in reinforced cement concrete. Bond strength and its importance in structural applications based on available standards attracted researchers around the globe to evaluate the bond strength in reinforced cement concrete through various test methods and procedures. In this review article, more than 200 globally published studies were collected, and 170 articles were compiled to discuss the importance of bond strength and the factors that affect bond strength in concrete. The various factors/parameters that affect the bond strength, including concrete type and its properties, the reinforcement bar with its geometry and shape, environmental nature of the specimen with its testing methods and standards, and other miscellaneous factors, were comprehensively analyzed. We present a summary of the findings; a surprising fact was that every factor is responsible for developing bond strength in concrete in one way or another. [ABSTRACT FROM AUTHOR]

Due to the current concern with the environmental impacts produced by the construction industry, many studies have been conducted to capitalize on the advantages of waste to develop sustainable materials. The study reports an innovative, non-conventional cement-based composite material containing 10 wt.% vine shoot waste, representing a step forward toward the use of this lignocellulosic waste. The investigations were carried out using scanning electron microscopy with energy dispersive X-ray analysis, Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and solid-state 27Al and 29Si nuclear magnetic resonance spectroscopy. The addition of vine shoot waste to the cement paste increases the amount of hydration products (calcium silicate hydrate (CSH), calcium hydroxide (CH), calcium carbonate (CaCO3) and ettringite), leading to a more compact and dense structure. The structural characterization techniques also confirmed the formation of a higher amount of hydration products in the case of vine shoot waste added to the cement paste. [ABSTRACT FROM AUTHOR]

Aging infrastructure is a threatening issue throughout the world. Long exposure to oxygen and moisture causes premature corrosion of reinforced concrete structures leading to the collapse of the structures. As a consequence, real-time monitoring of civil structures for rust becomes critical in avoiding mishaps. Muon scattering tomography is a non-destructive, non-invasive technique which has shown impressive results in 3D imaging of civil structures. This paper explores the application of advanced machine learning techniques in identifying a rusted reinforced concrete rebar using muon scattering tomography. To achieve this, we have simulated the performance of an imaging prototype setup, designed to carry out muon scattering tomography, to precisely measure the rust percentage in a rusted rebar. We have produced a 2D image based on the projected 3D scattering vertices of the muons and used the scattering vertex density and average deviation angle per pixel as the distinguishing parameter for the analysis. A filtering algorithm, namely the Pattern Recognition Method, has been employed to eliminate background noise. Since this problem boils down to whether or not the material being analyzed is rust, i.e., a classification problem, we have adopted the well-known machine learning algorithm Support Vector Machine to identify rust in the rusted reinforced cement concrete structure. It was observed that the trained model could easily identify 30% of rust in the structure with a nominal exposure of 30 days within a small error range of 7.3%. [ABSTRACT FROM AUTHOR]

Over the last few years, the addition of small amounts of carbon nanotubes (CNTs) to construction materials has become of great interest, since it enhances some of the mechanical, electrical and thermal properties of the cement. In this sense, single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs, respectively) can be incorporated into cement to achieve the above-mentioned improved features. Thus, the current study presents the results of the addition of SWCNTs and MWCNTs on the microstructure and the physical properties of the cement paste. Density was measured through He pycnometry and the mass change was studied by thermogravimetric analysis (TGA). The microstructure and the phases were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Finally, the electrical conductivity for different CNT concentrations was measured, and an exponential increase of the conductivity with concentration was observed. This last result opens the possibility for these materials to be used in a high variety of fields, such as space intelligent systems with novel electrical and electronic applications. [ABSTRACT FROM AUTHOR]

Non-destructive testing is needed for the evaluation of quality and safety of concrete structures in the field of civil engineering. The imaging of concrete/reinforced cement concrete structures (RCC) is a challenging task due to the non-homogeneous properties of the concrete material. To address this challenge, a novel real-time, re-configurable, four-channel embedded system has been designed and developed to image the internal details of the concrete samples using the water immersion pulse-echo (PE) mode under automation, which needs access from one side of the structure. The system performs data acquisition (DAQ) of the amplified echo signals under the control of the computer via a universal serial bus interface. A graphical user interface (GUI) has been developed using C# in a Visual environment, for image acquisition and control of the DAQ parameters. The performance of the system has been evaluated by acquiring B-Scan images of three types of concrete test blocks having side drilled holes (SDHs) and simulated inclusions embedded in concrete blocks of M20 grade using a linear array of 92 kHz water immersion transducers operating in under-water PE mode. The acquired B-Scan images revealed the internal details of the concrete test blocks with sizing of the SDHs and inclusions. Therefore, the developed four-channel ultrasonic imaging system can visualize the internal details of under-water concrete structures, such as bridges and sea links, with the help of corresponding 2-D cross-sectional images, acquired using the developed system. [ABSTRACT FROM AUTHOR]

In the domestic sector, buildings contribute to about 55% of the total energy consumption for space heating and cooling. In this study, an experiment was carried out using a square shape building prototype made up of laminated plywood with Reinforced Cement Concrete (RCC) roof. Surface treatment of four types of reflective paints was applied on the RCC roof slab. Their performance was monitored in the summer season (April and May). Based on the peak temperature of interior and exterior roof layers, several important parameters, such as temperature, indoor thermal amplitude, time lag, decrement factor, thermal damping, thermal performance index, peak degree hours and thermal performance of each roof slab, were analysed. The application of cool roofs (CR-1, CR-2, CR-3, and CR-4) shows a significant reduction in indoor temperature (2.1°C–3.2°C), and indoor thermal amplitude (16.10%–27.94%) compared to a standard RCC roof. The drops in peak temperature of exterior and interior roof layers were 4.8°C–6.8°C and 3.9°C–6.3°C, respectively. A significant improvement was achieved in time lag and decrement factor (3–4 h more than the reinforced concrete roof), with energy savings varying from 10.58% to 13.73%. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials opens a novel pathway for enhancing the mechanical properties and reinforcement effectiveness of cement-based materials. However, due to their high cost and reliance on specialized production processes, carbon nanomaterials have not been widely applied in practical engineering. Therefore, deposited nanocarbon (DNC), a byproduct of hydrogen production via methane pyrolysis, is utilized to enhance the performance of cement mortar. In this study, through uniaxial compression tests combined with acoustic emission (AE) technology, the entire fracture process of cement mortar with varying DNC dosages was comprehensively monitored. Microscopic characterization of the fracture surface was conducted using scanning electron microscopy. Scanning electron microscopy was employed to conduct microscopic characterization of the fracture surface, cement hydration products, and the bonding condition of slurry-aggregate interface. The results indicate that the compressive strength of DNC-modified cement mortar increases by 6.3–31.5 %, and the elastic modulus increases by 17.9–34.6 %. Additionally, the incorporation of DNC effectively reduces the AE counts during the early stages of sample failure. Furthermore, DNC promotes the formation of denser hydration products, filling voids and reducing micro-cracks and micro-pores in the hardened cement paste. This effectively reduces the width of the interfacial transition zone (ITZ) between fly ash and cement paste (by approximately 30.4–52.0 %), enhancing the interfacial bonding performance between the aggregate and the hardened cement paste. The proposed use of DNC offers a novel approach for achieving efficient resource recycling, promoting the widespread application of nanocarbon-modified cement mortar, and fostering sustainable development. • Deposited nanocarbon was prepared by chemical vapor deposition. • Cement mortar can be enhanced with deposited nanocarbon. • Deposited nanocarbon can improve the microstructure of cement. [ABSTRACT FROM AUTHOR]

Graphene reinforced cement composites (GRCCs) have attracted great attention due to their excellent mechanical and physical properties. Instead of uniform distribution, the functionally graded distribution of graphene fillers can effectively utilize the mechanical and physical properties of the reinforcements while reducing cost. This paper is the first attempt to combine experimental analysis and theoretical modelling to investigate the thermomechanical properties of functionally graded graphene nanoplatelet (GNP) reinforced cement composites (FG-GNPRCCs). Samples with uniform (profile H) and functionally graded (profiles X, O and A) distribution of GNPs were prepared and tested. Among all the FG distribution patterns as involved, profile X exhibited the most pronounced enhancement. Compared to the uniform distribution at room temperature, the loss factor and storage modulus of profile X increased by 19.3 % and 19.5 %, respectively. Based on the effective medium theory (EMT) and Mori-Tanaka (MT) model, a parallel triple-inclusion model was developed to predict the thermal conductivity of GNPRCCs. The effects of coated GNP, agglomeration and the attributes of pores (i.e., size, shape and porosity) on the thermomechanical properties of the composites were considered. Dynamic mechanical analysis revealed that profile X had the best energy dissipation and the extent of inelastic deformation within the temperature range from −50 °C to 70 °C. In contrast, profile A is beneficial for scenarios that desire a gradual transition and controlled stress along a certain direction. [ABSTRACT FROM AUTHOR]

Reinforced concrete structures, particularly in cold areas, experience early deterioration due to steel corrosion. Fiber-Reinforced Concrete (FRC) is an emerging construction material and cost-effective substitute for conventional concrete to enhance the durability and resistance against crack development. This article examines the structural performance of hybrid ferro fiber reinforced concrete slabs (mix ratio of mortar 1:2) comprising silica fume, layers of spot-welded mesh and different ratios of polypropylene fibers. The ferrocement slabs are compared with a conventional Reinforced Cement Concrete (RCC) slab (mix ratio of 1:2:4). The experimental work comprised a total of 13 one-way slabs, one control specimen and three groups of ferrocement slabs divided based on different percentages of Poly Propylene Fibers (PPF) corresponding to 0.10%, 0.30% and 0.50% dosage in each group. Furthermore, in each group, the percentage of steel ratio in ferrocement slabs varied between 25% and 100% of the steel area in the reinforced concrete control slab specimen. For evaluating the structural performance, the observation of deflection, stress-strain behavior, cracking load and energy absorption are critical parameters assessed using LVDTs and strain gauges. At the same time, the slabs were tested in flexure mode with third point loading. The experimental results showed that the first cracking load and ultimate deflection for fibrous specimens with 0.5% fiber and 10% silica fume increased by 15.25% and 13.2% compared with the reference RCC control slab. Therefore, by increasing the percentage of PPF and steel wire mesh reinforcement in the ferrocement slab, the post-cracking behavior in terms of deflection properties and energy absorption capacity was substantially enhanced compared to the RCC control slab. [ABSTRACT FROM AUTHOR]

The sound insulation defects of single-layer GRC（glass-fiber reinforced cement） perforated slats light partition wall commonly used in existing buildings are discussed. By comparing and analyzing the sound insulation characteristics of GRC perforated batten double wall and GRC perforated batten partition wall with composite sound insulation components, the advantages of composite sound insulation structure in the reconstruction of existing buildings are found. Firstly, the physical properties of acoustic materials and the characteristics of the composite structure with air interlayer in the composite sound insulation structure are studied, and the composite sound insulation structure is theoretically analyzed and experimentally tested. By optimizing the composite sound insulation structure, the design scheme of improving the sound insulation performance of GRC perforated slatted light partition wall with two layers and three layers of calcium silicate board composite structure is put forward. The results show that the modified GRC perforated partition wall can effectively improve the problem of sound insulation reduction caused by wall vibration, and improve the sound insulation performance of the wall in all frequency bands. [ABSTRACT FROM AUTHOR]

To further optimise the bullet-proof performance of textile reinforced composites, multi-directional friction tests of aramid and ultrahigh molecular weight polyethylene (UHMWPE) yarns were carried out by the slope method. The influence of the included angle between the high-performance yarns on the static friction coefficient for aramid and UHMWPE yarns was studied by measuring the friction coefficient. The relationship between the static friction coefficient and the included angle among the high-performance yarns was discussed. The results showed that the friction coefficient of aramid yarns was higher than that of UHMWPE yarns. Especially, at the same included angle between high-performance yarns, the static frictional coefficient of aramid yarns is 50% higher than that of UHMWPE yarns. In accordance with expectations, the static friction coefficient decreases with the increased included angle between high-performance yarns, and the included angle of high-performance yarns changes from 0º to 90º. The trend of rapid decline appeared when the included angle between high-performance yarns changed from 0º to 15º. For the actual result, the static friction coefficient of aramid and UHMWPE yarns is less than 0.3, which needs to be improved to increase the bullet-proof performance of textile composites. [ABSTRACT FROM AUTHOR]

Reinforced cement concrete (RCC) is a versatile material that deteriorates over time due to corrosion when exposed to any surrounding aggressive environment. In order to avoid this ramification, many researchers have carried out different work to find the most feasible way to reduce corrosion. To tackle this at the initial stage itself, one such convenient method is through the application of inhibitors. These inhibitors have most applications in their use as an admixture. This review paper mainly focuses on the inhibitor and its types, the drawbacks of inorganic, commercial organic, and hybrid inhibitors, and application to RCC, and also provides detailed information on green corrosion inhibitors (GCI). In recent years, widespread attention has been paid towards the utilization of different natural plant components/parts in concrete structures. This review paper consolidates the work done by various researchers using different GCIs with the main focus on plant extracts as an additive to concrete or RCC specimens which will be significant to sustainable progress in the field of corrosion. [ABSTRACT FROM AUTHOR]

Fly ash becomes a fine gray particles consisting generally of globular, smooth particles available in coal‐fired power stations. In this work, the seismic performance of beam‐column connection (BCC) has been examined by applying fly ash as a surrogate of cement. Five different samples of BCC's, with or without admixtures were casted as well as examined in order to obtain the hysteric loading characteristics for a curing period of 90 days. The tested samples designed for M25 grade of concrete having water–binder ratio maintaining as 0.4. From the study, it has been found that BCC sample having 20% fly ash along with super plasticizer subjected to 90 days curing (i.e., BCC sample of 20FAS90) exhibits a better performance as compared to the other tested samples. The BCC sample of 20FAS90 showed higher displacement as compared to controlled concrete without fly ash and super plasticizer at 90 days (Control90). Also, from the experimental work, it has been found that 20FAS90 sample possesses 18% higher ductility as well as 70% higher energy dissipation than the Control90 sample. Additionally, regarding brittleness index (BI) of 20FAS90 sample exhibits 25% lower as compared to Control90 sample. Furthermore, the stiffness degradation of the sample becomes slightly higher than the controlled concrete. Therefore, the paper essentially highlights the importance of fly ash and super plasticizer on the dynamic performance of the BCC samples at 90 days curing period such that an advanced mix design criterion could be put forward for optimum replacement of cement leading to higher safety aspects. [ABSTRACT FROM AUTHOR]

Reinforced cement concrete (RCC) is universally acknowledged as a low-cost, rigid, and high-strength construction material. Major structures like buildings, bridges, dams, etc., are made of RCC and subjected to repetitive loading during their service life for which structural performance deteriorates with time. Bridges and high-rise structures, being above ground level, are hard to equip with the contact mechanical methods to inspect strains and displacements for structural health monitoring (SHM). A non-contact, optical and computer vision based full field measuring technique called digital image correlation (DIC) technique was developed in the recent past to specifically evaluate bridge decks. Generally, optical images of structure in field conditions are not acquired precisely perpendicular to the object, which instinctively affects the deformation results obtained during loading conditions. An unmanned aerial vehicle (UAV) equipped with DIC vision-based technique acts as a rapid and cost-effective tool to quantify the serviceability of bridges by measuring strains and displacements at inaccessible locations. In this study, a non-contact unmanned aerial vehicle image correlation (UAVIC) technique is used on a scaled bridge girder and a contact method of measuring deformations with a dial gauge. Both investigations are correlated for accuracy assessment, and it is understood that results in laboratory conditions are 90% accurate. Similarly, the UAVIC technique is also performed on a rail over the bridge in the field conditions to understand the feasibility of the proposed method and evaluate damage quantification of it. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2)-cured concrete is a novel material that can effectively reduce CO2 emissions in the atmosphere. However, limited research has been found to investigate the corrosion behavior of CO2-cured reinforced concrete. In this paper, the corrosion resistance of reinforced cement mortar is investigated. The mortars were cured in CO2 for 1 day~28 days. Water–cement ratios (w/c) of 0.3, 0.4 and 0.5 were designed. The corrosion resistance of inner steel bars was researched by the methods of ultrasonic velocity, electrical parameters (AC electrical resistance, Tafel curve method and AC impedance spectroscopy). Moreover, scanning electron microscope was selected for observing the micro-morphology of CO2-curing mortar. X-ray diffraction spectrum was used to characterize components of steel bars' passive films. The results show that CO2 can effectively increase electrical resistivity and ultrasonic velocity, thus improving the corrosion resistance of reinforced cement mortar. The enhancement of carbon dioxide curing increases with the increasing w/c. The mass-loss rate, the electrical resistivity and the decreasing rate of ultrasonic velocity increase with the increasing sodium chloride freeze–thaw cycles, indicating the continuous increase in the corrosion degree of reinforcement. The corrosion deterioration degree of steel bars decreases with the increasing CO2-curing time. Specimens with w/c of 0.3 and 0.4 show the highest and lowest corrosion deterioration resistances after sodium chloride freeze–thaw cycles. Microscopic characterization found that CO2 curing could increase the corrosion resistance of the inner steel bars by improving the compactness of the cement matrix. Moreover, the iron oxides on the surface of the passivation film decreased after CO2 curing. [ABSTRACT FROM AUTHOR]