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The beneficial effect of microbially induced carbonate precipitation on building materials has been gradually disclosed in the last decade. After the first applications of on historical stones, promising results were obtained with the respect of improved durability. An extensive study then followed on the application of this environmentally friendly and compatible material on a currently widely used construction material, concrete. This review is focused on the discussion of the impact of the two main applications, bacterial surface treatment and bacteria based crack repair, on concrete durability. Special attention was paid to the choice of suitable bacteria and the metabolic pathway aiming at their functionality in concrete environment. Interactions between bacterial cells and cementitious matrix were also elaborated. Furthermore, recommendations to improve the effectiveness of bacterial treatment are provided. Limitations of current studies, updated applications and future application perspectives are shortly outlined.

Moisture transport in building materials significantly influences their durability, mechanical integrity, and thermal performance. This study presents an experimental investigation of moisture permeability in a range of traditional and modern wall elements, including autoclaved aerated concrete (ACC), ceramic blocks, silicate blocks, perlite concrete blocks, and concrete units. Both vapor diffusion and capillary transport mechanisms were analyzed under controlled climatic conditions using gravimetric and hygrometric methods. Among the tested materials, autoclaved aerated concrete (AAC) was selected for detailed numerical modeling because of its high porosity, strong capillarity, and widespread use in modern construction, which make it especially vulnerable to moisture-related degradation. Based on the experimental findings, a digital twin was developed to simulate hygrothermal behavior of walls made of ACC under various environmental conditions. The model incorporates advanced moisture transport equations, capturing diffusion and capillary effects while considering real-world variables, such as relative humidity, temperature fluctuations, and wetting–drying cycles. Calibration demonstrated strong agreement with experimental data, enabling reliable predictions of moisture behavior over extended exposure scenarios. This integrated approach provides a robust engineering tool for assessing the long-term material performance of AAC, predicting degradation risks, and optimizing material selection in humid climates. The study illustrates how coupling experimental data with digital modeling can enhance the design of moisture-resistant and durable building envelopes.

Over the last two decades, the repair of existing engineering structures using fiber reinforced polymer composites has attracted a great attention by aerospace industry, as it is more economical than replacing new. With an increased use of composite material in aerospace field, it is thus essential to restore the structural integrity by repair of damaged part. Concerns regarding the long term durability of composite repair bonded joints have been a major obstacle for critical component of aerospace structures. This paper reviews the current research on the environmental durability of adhesive bonded repair of composite structures to focus on the durability concerns and suggestion on the research needed in this area. The most important environmental factors (moisture and temperature) are reviewed thoroughly and also combined environmental effect. Finite element methods used to predict the environmental influence on the composite bonded joints are briefly reviewed. Finally, the paper concludes with key findings, opportunities and future research topics in order to develop cost effective, better quality and reliable composite repair bonded joints.

Rapid-strength concretes are currently used to repair structures such as bridge decks, substructure elements on bridges (for example, piers and columns), pavements, and components of buildings. Although these products gain a high strength in a short period of time (for example, [greater than or equal to] 20 MP a [3000 psi] in 3 hours), it is usually intended that they not only provide a temporary fix but can also provide a permanent repair for the remaining service life of the structure. One approach for delivering high early-age strength is through the rapid formation of ettringite using a binder that contains a calcium aluminate or calcium sulfoaluminate phase with calcium sulfate. Although it has been proven that such binders gain high early strength and acceptable working time, limited information exists concerning the long-term durability of concrete produced with these binders in the aggressive conditions often encountered in service. This paper presents durability data on the chloride resistance, corrosion protection properties, deicer salt scaling and carbonation resistance. These concretes include: portland cement (PC) and high-early-strength portland cement (HEPC) as references; a newly developed ternary cement (PC-CAC-CS) consisting of a blend of PC, calcium aluminate cement (CAC), and calcium sulfate (CS); and two commercially available calcium-sulfoaluminate (CSA) cement systems. Keywords: calcium aluminate cement; calcium sulfoaluminate cement; carbonation; chloride ingress; corrosion; durability; linear polarization; scaling resistance.

Life cycle assessment enables the identification of a broad range of potential environmental impacts occurring across the entire life of a product, from its design through to its eventual disposal or reuse. The need for life cycle assessment to inform environmental design within the built environment is critical, due to the complex range of materials and processes required to construct and manage our buildings and infrastructure systems. After outlining the framework for life cycle assessment, this book uses a range of case studies to demonstrate the innovative input-output-based hybrid approach for compiling a life cycle inventory. This approach enables a comprehensive analysis of a broad range of resource requirements and environmental outputs so that the potential environmental impacts of a building or infrastructure system can be ascertained. These case studies cover a range of elements that are part of the built environment, including a residential building, a commercial office building and a wind turbine, as well as individual building components such as a residential-scale photovoltaic system. Comprehensively introducing and demonstrating the uses and benefits of life cycle assessment for built environment projects, this book will show you how to assess the environmental performance of your clients' projects, to compare design options across their entire life and to identify opportunities for improving environmental performance.

In 1976, production of separately ground, pelletized blast-furnace slag started near Hamilton, ON, Canada, and a research program began in 1977 to study the effects of this slag cement on sulfate resistance of concrete. For this purpose, concrete cylinders were cast from eight batches using normal, moderate sulfate-resistant and highly sulfate-resistant portland cement types as well as mixtures of high-CsA portland cement plus slag at a water-cementitious materials ratio (w/cm) of 0.45 or 0.50. In the present study, samples were cut from concrete cylinders after 38 years of exposure to sodium sulfate solutions and thin sections were prepared for analysis using scanning electron microscopy. Micro-structural details were investigated from the exposed surface to the center of each cylinder, and different phases were determined. Ettringite, thaumasite, gypsum, and layers of calcium carbonate were found to have formed in the samples. A 65% slag substitution of high-[C.sub.3]A portland cement was very effective in improving the performance of concrete exposed to sodium sulfate. Keywords: concrete durability; ettringite; slag; sulfate attack.

Although concrete has a significant environmental impact, it also offers interesting opportunities of recycling waste materials that may improve its sustainability. Together with different other industrial residues that are normally recycled in concrete, expanded glass can be used as a lightweight aggregate. However, the use of glass in concrete raises concerns about durability because of its poor stability in alkaline environments. This paper presents a study aimed at investigating the durability of lightweight concrete (LWC) made with expanded glass and silica fume used, respectively, for the replacement of the fine fraction of aggregate and as mineral addition. Expanded glass particles were characterized in terms of alkali-aggregate reaction, density, absorption, and microstructure. The combination of expanded glass and silica fume led to a structural lightweight concrete that was able to maintain its strength under exposure to moist and hot conditions and showed high resistance to the penetration of aggressive agents.

The aim of this study was to develop a novel method for evaluating the service life of building coatings. In Stage 1, we assessed existing methods for determining the degree of fungal overgrowth on building materials (visual assessment, culture method, luminometric ATP (adenosine-5’-triphosphate) measurement, and spectrophotometric assessment of colour changes). Laboratory tests were carried out for 19 types of facade coating (mineral and silicone with/without primer, silicone paint, biocides) and 7 fungal strains (moulds Alternaria alternata, Aspergillus niger, Aureobasidium melanogenum, Cladosporium cladosporioides, Fusarium sp., Penicillium citrinum, and the yeast Rhodotorula mucilaginosa). The number of fungi on the facade coatings after 28 days of incubation was 1.7 × 105–4.6 × 105 CFUs (colony-forming units)/sample. The ATP content was 12 RLUs–30333 RLUs (relative light units). Colour change was ΔE > 5 depending on the coating type and fungal strain. A high or very high correlation was found between the ATP concentration (RLUs), colour change (ΔE), and the results of the culture method (CFUs/sample). In Stage 2, a new methodology for evaluating the protection lifetime of building coatings against fungi was developed, taking into account environmental conditions (impact of ultraviolet radiation, precipitation, presence of organic matter on the surface, quantitative and qualitative composition of bioaerosol). The developed method consists of one research cycle conducted in the laboratory, corresponding to one year under natural conditions. Preliminary verification showed the model to be compatible with long-term observations (3 years) of fungal growth on the facade coatings under real environmental conditions. The novel method could be used to design biodeterioration control and protection strategies for both new and cultural heritage buildings.

The compatibility of two shrinkage-reducing admixtures (SRAs) with two air-entraining admixtures (AEAs)--one surfactant-based and one foaming polymer-based--was examined based on freezing-and-thawing durability, scaling resistance, and air-void characteristics of hardened concrete. SRA dosages of 0, 0.5, 1.0, and 2.0% by weight of cement were used. Test results show that interactions between admixtures can reduce air-void stability, contributing to lowered freezing-and-thawing durability and scaling resistance. Without an SRA, concrete mixtures containing either AEA exhibited good freezing-and-thawing durability and scaling resistance. With an SRA, mixtures containing the surfactant-based AEA performed well, while those containing the polymer-based AEA did not. Mixtures containing higher dosages of SRA, regardless of AEA, experienced a greater loss in air content in concrete between the plastic and hardened conditions. Mixtures with an increased air-void spacing factor experienced decreased durability, with the greatest decrease observed in those with air-void spacing factors greater than 0.008 in. (0.20 mm). Keywords: admixtures; air-void analysis; freezing-and-thawing durability; scaling resistance; shrinkage.

This paper presents a durability study of cementitious composites mixed with seven Tunisian blended cements (portland limestone cement-cement [PLC-cement]) manufactured on an industrial scale with a varying limestone filler content (up to 35%). The durability tests were performed on mortars and concretes according to existing standards. The results show that limestone filler has different effects on the durability of composites, depending on the limestone amounts and the grinding quality of binders. Thus, they improve concrete resistance to the leaching of calcium ions into mono-distilled water, particularly when they are finer (more 99% of limestone < 40 [micro]m). Furthermore, limestone does not alter the resistance to the sulfate ion attack when its content does not exceed 25%. However, freezing and thawing causes rapid deterioration (decrease) in mechanical properties if the limestone content is higher than 25%. These results can serve as a recommendation for using PLC-cements in countries where they are rarely used. Keywords: durability; freezing and thawing; grinding quality; portland limestone cement-cement (PLC-cement); pure water; sulfate.