Calcium aluminate cement (CAC)—based strain hardening cementitious composites (SHCC) has been developed and used for the rehabilitation of sewerage pipelines. In addition to well-known microbiologically induced corrosion, CO₂ concentration in the sewerage environment is high, which may cause significant carbonation of pipelines. Thus, this paper aims to investigate the effects of carbonation on the mechanical performance of CAC-based SHCC. Two types of CAC-based SHCC with different strength grades and a referenced OPC-based SHCC were prepared. The accelerated carbonation test was conducted in a carbonation chamber with a 5% CO₂ concentration. The compressive and tensile behaviour of SHCC was tested first, and microstructure analysis, e.g., X-ray diffraction and scanning electron microscopy, was then performed. The results showed that CAC-based SHCC specimens exhibited robust strain-hardening performance as well as large deformation capacity in tension due to the fiber-bridging effect. Also, the compressive and tensile strength was significantly improved as well as achieving a higher tensile strain capacity after carbonation when compared with OPC-based SHCC. Microstructure analysis revealed that the metastable phases in carbonated CAC-based SHCC were converted into stable phases and calcium carbonate polymorphs, densifying the binder matrix. The obtained results of this paper may provide new insight into utilizing carbonation to avoid the unstable conversion of hydrates in calcium aluminate cement.

Herein the biowaste by-product spent coffee grounds (SCGs) from coffee industry were incorporated into asphalt binders for performance enhancement. From the analysis of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic shear rheometer (DSR), and Brookfield viscosity rheometer, it is confirmed that SCGs have potential prospects as bio-waste modifiers in the application of sustainable pavements. Results demonstrated that the modification process was mainly based on physical reinforcement. Compared with that of the neat asphalt, the shearing stress-resistant ability and high-temperature performance of the SCGs modified binders with the appropriate addition presented a bit of improvement; whereas the binders with 1% and 3% SCGs exhibited remarkably enhanced low-temperature stability. However, notable weaknesses of practical performance were shown for the binder with excessive content of SCGs, indicating the necessity of proportion selecting before application.

Limestone Calcined Clay Cement (LC³ is a newly proposed low-carbon cement, which can effectively reduce energy consumption and carbon emissions of the traditional cement industry without changing the basic mechanical properties of cement-based materials. In this study, the degradation process of mortar samples of limestone and calcined clay cementitious material under sulfate attack is studied by both macroscopic and microscopic analysis. The results show that compared with pure Portland cement, the addition of calcined clay and limestone can significantly reduce the expansion rate, loss of dynamic modulus and mass loss of mortar specimens under sulfate attack. The addition of calcined clay and limestone will refine the pore size distribution of mortar specimens, then inhibiting the diffusion of sulfate and formation of corrosive products, therefore leading to a significant improvement of the sulfate resistance.

This paper investigated the compressive behavior of a novel glass fiber reinforced polymer (GFRP)-timber-reinforced concrete composite column (GTRC column), which consisted of reinforced concrete with an outer GFRP laminate and a paulownia timber core. The axial compression tests were performed on 13 specimens to validate the effects of various timber core diameters, slenderness ratios, and GFRP laminate layers/angles on the mechanical behaviors. Test results indicated that with the increase in the timber core diameter, the ductility and energy dissipation ability of the composite column increased by 52.6% and 21.6%, respectively, whereas the ultimate load-bearing capacity and initial stiffness showed a slight decrease. In addition, the GFRP laminate considerably improved the ultimate load-bearing capacity, stiffness, ductility and energy dissipation capability by 212.1%, 26.6%, 64.3% and 3820%, accordingly. Moreover, considering the influence of timber core diameter, an ultimate load-bearing capacity adjustment coefficient was proposed. Finally, a formula was established based on the force equilibrium and superposition for predicting the axial bearing capacity of the GTRC columns. 

The research on the influencing factors of carbon emissions from urban buildings is of great significance for the reduction of carbon in the urban building sector and even the realization of the city’s the carbon peak and neutrality goals. In this paper, combined with the ridge regression method, the STIRPAT model is used to establish a new model for influencing factors of building carbon emissions in Suzhou, and the factors such as urbanization rate, the number of permanent residents, per capita construction and tertiary industry added value, and per capita disposable income are analyzed. The analysis results show that the urbanization rate is the primary driving factor for building carbon emissions in Suzhou, followed by the number of permanent residents, then the added value of the per capita construction industry and tertiary industry, and finally the per capita disposable income. The conclusions of this paper indicate that industrialization and urbanization have strongly promoted the growth of building carbon emissions in Suzhou. In the future, with the continuous development of industrialization and urbanization and the increase of population, Suzhou City can rationally plan urban development boundaries to promote green and low-carbon transformation and development in the field of urban and rural construction, improve residents’ low-carbon awareness, and advocate green and low-carbon behavior of residents to reduce building carbon emissions.

The shipbuilding industry is booming and the health problems of workers caused by the harsh indoor dock environment force us to explore efficient and reasonable ventilation methods suitable for large workshops. Due to the strong specificity of large workshops, general or local ventilation methods cannot be universally applied. It has great potential and good economy to improve indoor environment by changing natural ventilation design. Computational fluid dynamics (CFD) has gradually become a powerful tool for predicting indoor and outdoor airflow organization and optimizing indoor ventilation. This paper adopts CFD to study the effect of the inflow wind speed, the position of the side wall shutters, the area ratio and form of roof ventilators on the effectiveness of natural ventilation in a large shipyard driven by wind pressure. The results show that the influence on total ventilation volume is more obvious when the intake side is shaded than the exhaust side. Different incoming wind speeds will affect the wind pressure at the ventilation position, which is the decisive external factor affecting the natural ventilation of docks. When the area ratio of roof ventilators increases to a certain extent, its continued increase has an insignificant effect on the total ventilation volume. The influence of changing the arrangement of the roof ventilator on the natural ventilation effect can be neglected when the area ratio is kept constant.

Carbon emissions from buildings account for approximately half of China's total social carbon emissions. Focusing only on the carbon emissions of building operation tends to neglect the carbon emissions of other related parts of the building sector, thus slowing down the progress of carbon peaking in the building sector. By applying life-cycle analysis to calculate carbon emissions throughout the building's life cycle, the performance of carbon emissions at each stage of building materials, construction, operation and end-of-life demolition can be identified, so that carbon reduction strategies in building design can be selected.. This paper constructed a method for calculating the carbon emissions of green buildings in whole-building life cycle, and conducted a summary analysis of the carbon emissions of 33 projects that were awarded green building certification. The study found that the Chinese Assessment Standard for Green Buildings has a significant effect on reducing the carbon emissions of buildings in whole-building life cycle. Compared with the current average operational carbon emissions of buildings in China, the carbon intensity of green public buildings is 41.43% lower under this standard and the carbon intensity of green residential buildings is 13.99% lower. A carbon correlation analysis of the provisions of the current Chinese Assessment Standard for Green Buildings was conducted, comparing the changes in the carbon intensity of buildings before and after the revision of the standards. The study concluded that the new version of the standards has a greater impact on public buildings than residential buildings, the requirement of carbon emission reduction in the production stage of building materials is strengthened in terms of carbon emission during the whole-building life cycle. This study addresses the current problem of unclear carbon emission reduction effect of green buildings. 

This study proposes a new auxetic-shaped steel plate shear walls (simply referred to as ASSPSWs) consisting of boundary members and built-in perforated infill plates. The connection type between the boundary members is a hinge joint. The hole forms on the infill plates include orthogonal ellipse-shaped (ASSPSW-OE) and orthogonal peanut-shaped (ASSPSW-OP). This paper studied the hysteretic performance of two steel plate shear walls’ types based on the finite element analysis method. Within the study context, a parametric analysis was carried out to investigate the influence of various factors, such as hole size and hole distance, on the seismic performance of steel plate shear walls (SPSWs). The results indicated that reducing the the ratio of the ligament thickness to ellipse major axis (t/D) in orthogonal ellipse-shaped SPSWs can effectively increase the porosity while reducing the bearing and energy dissipation capacities. Under the condition with the t/D unchanged, increasing the ratio of the major to minor axis of the ellipse (d/D) raises the porosity and does not significantly reduce the bearing capacity and energy dissipation capacity of the SPSWs. For orthogonal peanut-shaped SPSWs, the holes’ geometrical parameters significantly influence the hysteretic performance. Particularly, with the increase in the radial ratio of large to small circles in a peanut-shaped hole (R/r), the spacing between cells decreases. When drift exceeds 2%, the equivalent viscous damping ratio decreases sharply. Unlike the orthogonal ellipse-shaped SPSWs, changing the arrangement angle of peanut-shaped cells has no significant effect on orthogonal peanut-shaped SPSWs. However, the larger the angle, the greater the out-of-plane buckling of orthogonal ellipse-shaped SPSWs; thus, the energy dissipation capacity is reduced. The similarities lie in that the larger cell arrangement angle will make the steel plates have a complete stress field, and the bearing capacity will be slightly improved. When the cell arrangement angle (θ) is 45°, the SPSWs can develop high initial stiffness.

The determination of carbon emission from foundation pit engineering is a tough and complex project owing to its characteristics including large material consumption, short use time, difficult recycling and no operation stage. To overcome these limitations, the calculation boundary and calculation method for carbon emission of foundation pit project are defined in this paper, which is successfully applied in the carbon emission analysis of the actual engineering project, i.e. the construction of large-scale foundation pit of Kunming comprehensive transportation international hub. All the carbon emissions coresponding to four working stages including building materials production, building materials transportation, construction and demolition were calculated and anatomized. The results revealed that the content of CO₂ released in the stage of building materials production accounts for 89.3% of the total carbon emission, which means the amount of building materials consumed in the engineering project is the crucial factor to control the carbon emission. Besides, two kinds of carbon reduction measures, i.e. optimization design of support scheme and recycling waste materials of internal support demolition, were explored by analyzing the proportion and average value of carbon emission from different sub project of the support structure. A pronounced effect of carbon reduction was achieved. Furthermore, both a fast calculation method of carbon emission factor of unit work volume and general carbon reduction measures are proposed in this paper, which could provide a reference and new viewpoint for the engineers and designers to calculate and analyze the carbon emission and to take effective carbon reduction measures.

The COVID-19 pandemic encouraged the use of plastic-based personal protective equipment (PPE), which aided greatly in its management. However, the increased production and usage of these PPEs put a strain on the environment, especially in developing and underdeveloped countries. This has led various researchers to study low-cost and effective technologies for the recycling of these materials. One such material is disposable facemasks. However, previous studies have only been able to engage electrically powered reactors for their thermochemical conversion, which is a challenge as these reactors cannot be used in regions with an insufficient supply of electricity. In this study, the authors utilized a biomass-powered reactor for the conversion of waste disposable facemasks and almond leaves into hybrid biochar. The reactor, which is relatively cheap, simple to use, environmentally friendly, and modified for biochar production, is biomass-powered. The co-carbonization process, which lasted 100 min, produced a 46% biochar yield, which is higher than previously obtained biochar yields by other researchers. The biochar thus obtained was characterized to determine its properties. FTIR analysis showed that the biochar contained functional groups such as alkenes, alkynes, hydroxyls, amines, and carbonyls. The EDX analysis revealed that the biochar was primarily made of carbon, tellurium, oxygen, and calcium in the ratios of 57%, 19%, 9%, and 7%, respectively. The inclusion of the facemask decreased the surface area and porosity of the biochar material, as evidenced by its surface area and pore characteristics.

The complete description of outdoor luminous and thermal environment is the basis for daylight utilization design with simulation tools. Nevertheless, Typical Meteorological Year (TMY) and generation method specifically developed for the energy simulation of daylight-utilized buildings is still unavailable currently. Luminous environment parameters have not been taken into consideration in existing TMY generation methods. In this study, the feasibility of existing TMY generation process has been examined. A generic office model implementing sided window daylighting is established. Historical meteorological data of Hong Kong from 1979 to 2007 have been collected and three existing weighting schemes are applied during the Typical Meteorological Month (TMM) selection procedures. Three TMY files for Hong Kong are generated and used to conduct integrated Climate-Based Daylight Modeling and building energy simulation. The result demonstrates that, on annual basis, the energy consumption results obtained from the generated TMY files are in good agreements with the long-term mean annual value. The maximum deviation of annual energy consumptions for the generated TMY files is only 1.8%. However, further analysis on monthly basis shows that all the three generated TMY files fail to fully represent the long-term monthly mean level. The maximum deviation of monthly energy consumptions for the generated TMY files can reach up to 11%. As the energy performance daylight utilization is subject to weather change, analysis on daily and monthly energy level is important, especially during design stage. The deficiency of existing TMM selection process and TMY generation method indicates the necessity to develop a corresponding typical weather data input with finer resolution for the energy simulation of daylight-related buildings.

Industrialization has though brought comfort to our daily lives, but it has placed a lot of pressure on the planet’s natural resources, subsequently, it has adversely affected the environment. As the need for cement in the construction sector has grown, it has climbed dramatically globally. Around the world, more than 10 billion cubic meters of concrete are produced each year; it is doubtful that this volume will decrease. A significant expected rise in CO₂ emissions is caused by increased cement demand. According to the UN Environment Program, buildings are responsible for up to 41% of global anthropogenic carbon emissions. The primary source of greenhouse gases utilized in the manufacturing of cement is clinker. Due to the unsustainable supply of fly ash, calcined clay appears to be a better Supplemental Cementitious Material (SCMs). Kaolin clay is widely available in Pakistan. The purpose of this investigation is to describe the mineral and thermal characteristics of Pakistani clays by examining their geographic distribution. Clay samples were gathered from 39 different places throughout Pakistan during a field investigation program. X-ray diffraction, X-ray Fluorescence, Reactivity, and thermogravimetric analyses were used to analyze the clay samples’ mineral content and thermal characteristics. This study demonstrates that Pakistan has a substantial amount of kaolin clay reserves close to existing groups of cement plants. Pakistani clays can be utilized as SCM in the production of limestone calcined clay cement (LC³) due to the country’s vast kaolin clay reserves. This study further supports the viability of producing LC³ in the nation by providing a thorough analysis of the cement business, known deposits of qualifying clay, and the country’s cement production process.

More than half of the annual global concrete materials were produced in China due to the rapid developing construction industry, which partly led to the shortage of river sand. However, mining rate exceeds the natural replenishment rate of river sand recently, resulting in depletion of natural river sand accumulation. The increasing demand of river sand influences lots of aspects including altered landforms, increasing carbon emissions, ecological deterioration, international trades and disputes. To face the river sand resource shortage in China and to propose possible coping strategies, the data of river sand for construction in China and other related data were collected, and it is suggested that effective policy measures should be taken right now to protect river sand and strictly manage sand mining. Professional solutions for river sand shortage can be summarized as “5Rs” principle, which includes reduce, recycle. reuse, replace and recover. System dynamic model is established to predict the trend of river sand shortage and it was predicted that the gap between river sand supply and demand will come up to 63%. The impact of three policy scenarios is tested in the model, and the gap can be reduced to 35% by single policy scenario, while the scenario with all policy measures is able to reduce the contradiction between supply and demand to 4%. Suggestions are proposed from the aspects of structural and material technology, policy measures and international alliances. Attention should be paid to the shortage of river resources, to realize the sustainable development of the construction industry and other related industries, and to promote the harmonious coexistence of human and nature.

On 6 February 2023 at 09.17 BST, an earthquake measuring 7.8 on the Richter scale struck the southern border of Turkey near Syria, causing massive casualties and building damage. Badly damaged buildings need to be demolished, bringing a large amount of demolition waste, which, if not properly disposed of, can be a burden on the environment. In this study, damage to buildings in the quake-hit areas of Turkey is investigated, including reinforced structures and masonry structures. Based on this, the amount of demolition waste produced and the proportion of waste components are estimated roughly. Ultimately, the paper puts forward the strategy of recycling demolition waste after the earthquake and the application scenario planning of recycled products. Conclusively, the amount of demolition waste generated after the earthquake ranges from 450 to 920 million tons, providing new ideas for post-disaster reconstruction work. Besides, post-disaster waste management, safe demolition and environmentally friendly disposal and recycling technologies for demolition and construction wastes will bring good economic and environmental benefits, help the reconstruction of disaster areas, and provide a model for the resource utilization of construction and demolition waste worldwide.

Underground engineering, including shield tunnel construction, is a significant contributor to carbon dioxide emissions in infrastructure engineering projects. To better predict and control the carbon emissions associated with shield tunnel construction, this paper presents a novel calculation method: the modified process analysis method based on input-output and process analysis methods. To evaluate the effectiveness of the proposed method, a specific shield tunnel construction project was selected as a case study. The modified process analysis method was used to analyze the various factors that influence carbon emissions during the project’s construction phase. In addition, a neural network approach was applied to validate the accuracy of the calculation using the LSTM and BP neural network. The results demonstrate that the proposed method not only combines the strengths of traditional methods but also offers high accuracy and acceptable error rates. Based on these findings, several measures to reduce carbon emissions during shield tunnel construction are suggested, providing valuable insights for reducing CO₂ emissions associated with infrastructure engineering projects. This study highlights the importance of adopting innovative approaches to reduce carbon emissions and promotes the implementation of sustainable practices in the construction industry. Through the use of advanced analytical methods, such as the proposed modified process analysis method, we can effectively mitigate the environmental impact of construction activities and make significant contributions to the global effort to combat climate change.

Bamboo Winding Composite Pipes (BWCPs) have many advantages such as good mechanical properties, low cost, low carbon, environmental friendliness, thermal insulation and easy installation et al. At present, BWCP is widely used in urban water supply, drainage, communication cable protection, farmland irrigation etc. It is obvious that the Bamboo Winding Composite materials have good application prospects in the field of utility tunnels. However, considering that the size of utility tunnels is much larger than that of normal pipelines, the wide application of Bamboo Composite Utility Tunnels (BCUTs) is still a challenge. In this paper, the force performance of BCUT in Datong Shanxi Province, was studied using two methods: real time monitoring and numerical simulation. Wireless sensor networks were used for monitoring, and the real time monitoring data of horizontal convergence and strains under the condition of backfill were obtained. The monitoring data indicated that the horizontal convergence can meet the requirement of relevant technical standards. A three-dimensional numerical model of the utility tunnel was established using FEM software. The influence of soil parameters on the deformation and strain of the BCUT was studied using the numerical method. The simulation results were compared with real-time monitoring data. The soil parameters K ₀ and k _sh have significant effects on the deformation, stress and strain of the utility tunnel. This kind of utility tunnel is recommended to use in areas with relatively good geological conditions.

W-Ag has applications in a wide range of cutting-edge fields, counting heat sinks and microwave absorbers for micro—electronic components, electric arc ends, and filaments for welding processes, electrical contacts, and durable electronic connections. Chemical methods provide a number of benefits, including improved purity, and controlled particle size. The present study focused on the fabrication of W-Ag nano composites using chemical synthesis. W-Ag nanocomposites with average size less than 50 nm were synthesized using Tungsten hexacarbonyl (W(CO)₆, and silver acetate (CH₃-COOAg) as metal precursors in the present study. The W-Ag composites were sintered using conventional sintering. X-ray diffraction studies of as-prepared powders showed amorphous W-phase and FCC Ag, while sintered W-Ag composites exhibited crystalline BCC W and FCC Ag phase. The effect of sintering temperature on relative density and mechanical properties of W-Ag sintered compacts was investigated. Relative density in excess of 97.6%, 98.2% and 98.8% was achieved for W-20.3 wt.% Ag, W-30.1 wt.% Ag and W-39.8 wt.% Ag composites on conventional sintering at 1000°C for 1 h. Vickers hardness of 364 ± 10 and 320 ± 8 Hv and 279 ± 6 were achieved for W-20.3 wt.% Ag, W-30.1 wt.% Ag and W-39.8 wt.% Ag composite compacts respectively. The hardness value of W-Ag composites decreased with an increase in Ag content. The combination of properties realized in this study renders the composites suitable for automotive and heat sink applications.

CO₂ sequestration/storage shows considerable impacts on the pore structures and compressive strength of concrete. This paper presents a study in which coral aggregates were presoaked in Ca(OH)₂ slurries with different solid-to-liquid ratios (i.e. 0.2, 0.4, and 0.6 g/mL) followed by accelerated carbonation. The effects of CO₂ sequestration on the particle size distribution, cylinder compressive strength, water absorption, and apparent density of coral aggregate were investigated. The evolution of pore structures in coral aggregate concrete after CO₂ sequestration was also studied. Additionally, the effect of CO₂ sequestration on the development of compressive strength of coral aggregate concrete was explored. The results showed that CO₂ sequestration affected the properties of coral aggregate. Moreover, the porosity of CaCO₃ formed by CO₂ sequestration was the highest in the concrete. With the increase of solid-to-liquid ratio, the porosity of cement pastes and the CaCO₃ increased, and more big pores existed in the cement pastes and CaCO₃. Furthermore, the compressive strength of coral aggregate concrete when the solid-to-liquid ratio was 0.2 g/mL increased compared with that before CO₂ sequestration, but the compressive strength reduced when the ratio increased to 0.6 g/mL.

The introduction of daylight can improve buildings’ energy efficiency and bring benefit to occupant satisfaction. However, the introduction of daylight may accompany with excessive heat. Properly counterbalancing the energy consumption of air conditioning and lighting systems owing to the entry of daylight is a critical control target of dynamic shading adjustment in cooling season. Most dynamic shading control strategies in use only consider one single system. Additionally, for advanced control mode like performance-based control, the predictive model usually only examines the instantaneous effect of energy performance to determine the shading adjustment state, unable to quantify the overall influence of shading adjustment state on building energy consumption. In order to address this issue, special consideration is given to calculating the cumulative contribution of heat gains to cooling load in this study. An overall energy-efficient shading control metric is proposed and used as basis to develop optimized dynamic shading control strategy. An application example demonstrates that the SGR-Optimal control strategy can further save energy by 21.8% ~ 38.8% when compared to the Rule-based control strategy, thus allowing a better exploration of the energy efficiency potential of daylight measure.

• Reviewed the valorization of different sludge and sludge ash in construction materials.

• Sludge can be recycled as alternative fuels and raw materials to produce eco-cement clinkers.

• Aluminosilicates in sludge/sludge ash improved the properties of construction materials.

• Sludge/sludge ash-derived function concrete, bricks and ceramic exhibit good qualities.

• Potential toxic elements in sludge/sludge ash could be effectively immobilized.

The influence of superplasticizer on the yield stress of cement pastes with recycled powder (RP) was examined in the study. Four superplasticizers were used to obtain the similar fluidity by adjusting the dosage. The results show that the 10% RP decreases the yield stress of paste compared to the reference paste at the same fluidity, but 20% and 30% RP increases the yield stress, ranging from 11 to 599%. The superplasticizer with adsorptive group of phosphate-type minimizes the yield stress of paste than that of polycarboxylate -type, but it made a significant increment in yield stress as the incorporating of RP increased. Besides, the polycarboxylate superplasticizer with the higher molecular weight of side chain and charge density led to lower yield stress. Based on the Yodel model, the yield stress of paste with RP was analyzed by the polymer adsorption and particle packing density of particles to reveal the influence of RP with different superplasticizers on the colloidal interaction and contact network among the particles. The packing density of particles with recycled powder was a little higher than the reference paste, but the higher fraction of fine particles made a stronger PSD effect, which improved the particle contact interaction. On the other hand, due to the higher polymer adsorption of recycled powder than cement, especially for superplasticizer with phosphate group, the average surface coverage was increased, which extended the separation distance, so that colloidal interaction among particles was weaken.

Geopolymer is produced through the polymerization of active aluminosilicate material with an alkaline activator, leading to the formation of a green, inorganic polymer binder. Geopolymer concrete (GPC) has become a promising low-carbon alternative to traditional Portland cement-based concrete (OPC). GPC-bonded reinforcing bars offer a promising alternative for concrete structures, boasting excellent geopolymer binder/reinforcement bonding and superior corrosion and high-temperature resistance compared to Portland cement. However, due to differences in the production process of GPC, there are distinct engineering property variations, including bonding characteristics. This literature review provides an examination of the manufacturing procedures of GPC, encompassing source materials, mix design, curing regimes, and other factors directly influencing concrete properties. Additionally, it delves into the bond mechanism, bond tests, and corresponding results that represent the bond characteristics. The main conclusions are that GPC generally has superior mechanical properties and bond performance compared to ordinary Portland cement concrete (OPC). However, proper standardization is needed for its production and performance tests to limit the contradictory results in the lab and on site.

Strength properties of laboratory scale lime-based samples enhanced with additives such as nanomaterials (nanofibrillated cellulose, nanosilica, nanoclay, expanded graphite), hemp & glass fibres, hemp shiv and polyvinyl acetate (PVAc) are determined. Samples were cured for 26 days in air at 20˚C / 60% RH after casting before being oven dried for a further two days at 50˚C (28 days total). Results show that the nanomaterials on their own had a mixed effect on the strength although nSiO₂ as a solo additive performed exceptionally well. The combination of fibres in conjunction with PVAc also greatly enhanced the strength due to increased bond between the fibres and the matrix. In addition, Greenhouse Gas emissions (GHG, kgCO₂eq) of an arbitrary block was determined for all composites and compared to the GHG of a commonly used lightweight aerated concrete block. Comparison of the normalised compressive strengths to the different loading conditions as outlined in BS EN 8103 shows that a more widespread use of pre-cast lime composites is possible and without unduly increasing GHG emissions.

A tremendous amount of non-biodegradable waste is created during mining and processing tasks of layered stones like marble. Over time, this has become a global problem because it harms the environment in multiple ways. Hence, it is necessary to find an alternate way to securely dispose and reuse marble wastes. The construction sector is one of the significant consumers of natural resources for the production of material binders and aggregates. As a result, in recent years, number of researchers have carried out studies in which various kinds of marble waste have been incorporated into concrete with the intention of substituting either cement or aggregates or both. This paper presents the effect of two locally sourced waste marble powders Kadapa marble powder (KMP) and Bethamcherla marble powder (BMP) as partial replacement of cement on mechanical and durability properties of high strength concrete (HSC). Their effect at different replacement levels in HSC is evaluated in compressive, indirect tensile and flexural strengths, elastic modulus, chloride penetration resistance and freeze–thaw durability properties. Micro-structural investigation is also conducted to evaluate their impact on the matrix of HSC containing waste marble powders as additional cementitious materials. Results show that the HSC consisting of KMP and BMP content of 10% and 15%, respectively exhibited higher mechanical and durability properties than the control HSC. Micro-structural investigation also supports this finding. It can be concluded that the use of marble powders as partial replacement of cement does not have any adverse impact on the properties of concrete. The use of KMP and BMP reduces the vast amount of energy required to produce cement, cost and time with reduction in environmental hazards.

• New artificial aggregates were produced from recycled alkali activated slag.

• Development of 131.8 N crushing force was achieved using optimal particle size of the raw material.

• It is possible to upcycle alkali activated slag waste to reduce landfill space and contribute circular economy.

• Produced aggregates can be used for example as an aggregate in lightweight concrete produce new green building materials.

Geopolymers are inorganic adhesive synthesized from industrial waste such as fly ash thus the development of wood geopolymer composite would be a low carbon footprint material. Geopolymers, being a non-formaldehyde adhesive can be used as an alternative binder for wood based composites where environmentally friendly and sustainability of product is important. In this study flyash as precursor is been used in the development of wood geopolymer composite product. Flyash is activated with a combination of sodium hydroxide and sodium silicate solutions at a weight ratio of 1:2.5 for geopolymer formation. The study investigated the properties of wood geopolymer composite made with ratios of wood particle to flyash percentage (23/77), (37/62), (44/55), (50/50) and (57/43). Geopolymer formation was observed by X-ray Diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Influence of wood particles in wood geopolymer composite were observed by Scanning electron microscope. The study shows that the water absorption and thickness selling properties of all the formulations of wood geopolymer composites are comparable with the medium density particle board and cement-bonded particleboard according to the IS:3087–2005 standard and IS: 12406: respectively. Highest mechanical properties and good bond strength was obtained by the composite containing 23% wood particle ratio with 77% percent flyash. However, still improvement in mechanical properties is needed to achieve the mechanical properties comparable to cement bonded particle board.

One of the biggest problems responsible of the nonrenewable resources depletion and environmental issues is the construction industries, which generates large amounts of mineral waste and harmful emitted gases. Therefore, these problems generated the necessity to search for alternative natural building materials based on renewable resources. To study the mechanical characteristics and microstructural behavior of the concrete reinforced by raw wheat straw basalt fiber composite (RWSBFc), and treated rice straw basalt fiber composite (TRSBFc), a number of experimental tests were carried out with different composites ratios. Concrete compressive strength, splitting tensile strength, and flexural strength tests were considered as main parameters. The results showed that the RWSBFC has a positive effect on concrete flexural strength by increasing of 12.58%, compared with control samples. Also, it showed good enhancement in concrete flexibility and ductility. In contrast, both RWSBFc and TRSBFc showed uneven deterioration in concrete compressive strength and splitting tensile strength. To avoid the deterioration in compressive strengths of the various composites types, some improvement methods such as processors for the used straw, and adding some additives were recommended.