The construction sector is the largest consumer of virgin and processed materials (Ghaffar et al., 2020). These range from quarrying to producing aggregate, cement and steel. These activities generate large amounts of carbon dioxide (CO2). For example, manufacturing one tonne of cement can generate up to one tonne of CO2 (Deja et al., 2010). Therefore, reducing the amount of cement used in construction activities by replacing it with industrial by-products or less embodied energy materials (Bawab et al., 2024; Ghazzawi et al., 2024), using recycled materials and improving the efficient utilisation of materials are considered to be key ways to reduce CO2 emission and thereby contribute to a sustainable future. This special issue is geared towards supporting the decarbonisation of the construction industry and comprises four broad themes, namely, Waste, Fibres, Repair, Building Life Cycle and Management. Each theme contains a number of papers written by prominent authors in the field of building and construction and from different global perspectives.
Using waste in construction should reduce the carbon footprint in that less virgin, quarried and processed materials will be used. The first theme (Waste) is concerned with the performance of construction materials containing waste products and has five papers. In the first paper, Haroon et al. (2025) assessed the performance of concrete incorporating demolished concrete powder (DCP) and found that replacing 20% cement with DCP can produce lightweight and more workable concrete with an adequate strength. The use of agro-waste and nano-materials in the production of eco-friendly concrete is the subject of the second paper, authored by Amran and Onaizi (2025). They concluded that it is possible to produce an eco-friendly concrete using agro-waste. The third paper in this theme, authored by Ghannoum et al. (2025), assessed the characteristics of reinforced concrete beams containing plastic waste using both experimental and numerical methods. They found that the maximum load carried by the beams and the crack propagation can be predicted using stochastic finite elements modelling. The effect of including glass waste on the characteristics of ultrahigh performance reinforced concrete beams is the subject of the fourth paper authored by Neamat et al. (2025). Cement was partially replaced with up to 30% glass powder. The authors showed that ultra-high performance reinforced concrete beams can be produced using 20% glass powder with minimum central deflection and minimum CO2 emission. The last paper of this theme, authored by Gurieva et al. (2025), investigated the production of ceramic bricks containing nickel slag waste. This waste is normally sent to landfill. Enhanced physical and mechanical performance of bricks was achieved in the presence of this waste which would have both economic and environmental advantages.
Adding fibre to construction materials is known to increase the tensile strength and control the propagation of cracks, thereby enhancing their durability. There are economic and environmental benefits if the fibres are coming from recycled sources or from local bio-materials. The second theme (Fibres) is about the use of different types of fibre in the production of concrete materials. In the first paper of this theme, Amran (2025) explored to possibility of using recycled steel tire fibre (RSTF) coming from tire waste in the production of sustainable concrete composites. This was part of Saudi waste management future strategies which is in line with Saudi Vision 2030. The study concluded that further investigation on the properties of concrete containing RSTF should be conducted. Also, there is a need to develop procedure for recycling and regulations to facilitate the implementation the use of RSTF in concrete composites. The second paper of this theme, authored by Ramadan et al. (2025), examined the mechanical properties and volume change of cement paste containing Phragmites australis (PA) bio-fibres. Adding 1% of PA fibre to the cement paste yielded optimum performance in terms of strength, expansion, autogenous and drying shrinkage. In the last paper of this theme, Ibrahim et al. (2025) conducted an experimental investigation on the effect of glass fibre on the mechanical and fracture properties of mortar containing cements with various levels of carbon footprint. Digital image correlation (DIC) technique was used to assess crack size and propagation. The presence of fibre caused an increase in the flexural strength of mortar. The width of crack and fracture energy were found to reduce when using cement with low carbon footprint.
Concrete structures are subjected to deterioration during their service life and in many cases repairing them is a viable option instead of total replacement. This would have more economic and environmental benefit. Therefore, the third theme (Repair) consists of two papers related to repair of concrete structures. In the first paper, authored by Hachem et al. (2025), examined the interfacial bond and shear strength of mortar containing metakaolin based geopolymer as repair materials and cement mortar as a substrate. Geopolymers are a total replacement of cement which has high embodied energy and high carbon footprint thus contributing to the decarbonisation of construction industry. They found that using geopolymer mortar as a repair has higher bond characteristics than using traditional cement mortar. Also using grooved repair surface has led to an improved bond strength compared with smooth surface. The next paper authored by Abubakri et al. (2025) explored the effect of microwave curing (MC) on the pore properties and moisture loss of repair mortars. As stated by the authors that compared with traditional accelerated curing, MC curing can provide several economic and environmental benefits including a shorter construction time, energy efficiency and lower cement content. Also, MC curing was found to increase the water loss from mortar specimens and there is a need to cover them during curing.
The fourth theme (Building Life Cycle) is concerned with the carbon emission of building products and concrete materials and consists of three papers. In the first paper, Sällström Eriksson and Lidelöw (2025) explored the benefits of either maintaining or replacing the windows in buildings in order to reduce the operational heating energy and the associated carbon emission. Using life cycle analysis, they found that generally maintaining the existing windows in building reduces cost and the climate impact. The second paper of this theme, Mensah et al. (2025) attempted to identify the causes of carbon emissions from buildings in Ghana urban environment. They identified some key factors which would contribute towards low carbon emissions from building. These include government policies and regulations. The use of local materials and technologies in construction plays a role in the reduction of carbon dioxide. The last paper, authored by Abdelgader et al. (2025), investigated the design method for concrete materials for the purpose of producing a mix with low carbon footprint that can be employed in the construction of buildings or other construction projects. They compared two concrete mix design methods; the Bolomey method and Abrams’ law method. The study concluded that a multi-criteria approach should be conducted including life cycle assessment in order to obtain a concrete mix that is cost effective and environmentally neutral.
The last and fifth theme (Management) of this special issue is focused on project management and its effect of reducing carbon emission of construction. The theme comprises three papers. The first paper, authored by Kusi et al. (2025), compared the CO2 emission and energy consumption of traditional buildings and green buildings using Building Information Modelling (BIM). They found that using green building model (BIM) can reduce the carbon emission by up to 47% and energy consumption by 25%. Also the BIM methodology can be used to retrofit existing buildings into green building to save energy and reduce carbon emission. In the second paper, Omer et al. (2025) suggested a procedure for identifying waste generation from construction activities. Their results indicated that problem-solving skills, communication skills and environmental awareness of construction activities are essential in reducing construction waste. The outcomes of their study should lead to an effective waste management by identifying activities where recyclable materials are produced. The outcomes of their study should lead to an effective waste management by identifying activities where recyclable materials are produced. In the last paper, Akter et al. (2025) evaluated the impact of using BIM as a lean management tool for the construction industry in Bangladesh. It was concluded that using BIM can improve the quality of construction, shorten the design process and avoid delay in construction. Reducing the construction time can reduce the construction cost and improving the quality of construction can increase the life span of the project, thereby reducing the frequency of maintenance and indirectly the associated carbon emission.
It is hoped that this special issue will raise awareness and assist construction professionals in taking appropriate steps for reducing carbon emission from construction activities. The improvement in the quality of materials would lead to low running cost and a reduction in CO2 emission, thus contributing towards sustainable development. This is in line with the United Nations (UN) sustainability goals and should improve the quality of life while conserving the world natural resources and preserving the natural habitat. Researchers and educators in the field of construction should benefit from the papers published in this issue to gain further insight into the reduction of carbon caused by the construction industry.
