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Recycled concrete is an economical and environmentally friendly green material. The shear performance of recycled concrete load-bearing masonry is studied, which is great of significance for its promotion and application and also has great significance for the sustainable development of energy materials.

In total, 30 new load-bearing block masonry samples of self-insulating recycled concrete are subjected to pure shear tests, and 42 samples are tested subjected to shear-compression composite shear tests. According to the axial design compression ratio, the test is separated into seven working conditions (0.1–0.8).

According to the test results, the recommended formula for the average shear strength along the joint section of recycled concrete block masonry is given, which can be used as a reference for engineering design. The measured shear-compression correlation curves of recycled concrete block masonry are drawn, and the proposed limits of three shear-compression failure characteristics are given. The recommended formula for the average shear strength of masonry under the theory of shear-friction with variable friction coefficient is given, providing a valuable reference for the formulation of relevant specifications and practical engineering design.

Simulated elastoplastic analysis and finite element modeling on the specimens are performed to verify the test results.

The purpose of this paper is to describe sustainability of hollow and solid blocks in sub-Saharan Africa.

Indicators of stakeholder value are proposed for measuring block sustainability based on comparisons of user building value price and carbon emissions. Block manufacturing processes in Tanzania and Uganda are described and assessed in this context.

The results from Uganda indicate that there are economic and environmental advantages in using hollow blocks as long as they are produced to statutory compliance levels. However, where blocks are not produced to standard requirements, the results indicate that it is better to use solid blocks. This surprising result seems to indicate that blocks prepared using low additions of cement might have sufficient functional quality for simple residential building applications even though they might not meet current standard strength requirements and have low cement productivity. These results also indicate that the improvement potential indicated previously cannot be realised when hollow blocks are used for simple construction needs.

Clear benchmarks for the best practical level of cement block sustainability seem to be missing. The first reasons is that the lowest acceptable compressive strength has not been defined since standard requirements might not be relevant in the studied context. The second one is that the lowest possible practically achievable cement content with acceptable cement productivity has not been established.

Understanding sustainability can be very difficult and substantial work needs to be done to introduce operational sustainability indicators.

The results contribute to the discussion of understanding, defining and measuring sustainability.

Infill materials play a pivotal role in determining buildings’ life cycle costing (LCC) and environmental impacts. International standards prescribe LCC and life cycle assessments (LCA) to assess materials’ economic and environmental sustainability. The existing methods of LCC and LCA are tedious and time-consuming, reducing their practical application. This study sought to integrate LCC and LCA with building information modeling (BIM) to develop a swift and efficient approach for evaluating the life cycle performance of infill materials.

The BIM model for a case study was prepared using Autodesk Revit®, and the study included four infill materials (lightweight aggregate concrete block (LECA), autoclaved cellular concrete (AAC), concrete masonry and bricks). LCC was conducted using Revit® and Autodesk Insight 360® to estimate costs incurred across different project phases. LCA was conducted using “One Click LCA®,” a BIM-based platform featuring a comprehensive material inventory. Carbon emissions, acidification, and eutrophication were chosen as environmental impact factors for LCA.

LECA was the preferred choice due to its lower cost and environmental impact. Its lifetime cost of $440,618 was 5.4% lower than bricks’, with 2.8% lower CO₂ emissions than AAC’s, which were second-place options, respectively. LECA had 6.4 and 27% lower costs than concrete blocks, and AAC’s carbon emissions were 32 and 58% lower than concrete blocks and bricks, respectively.

BIM has been employed for life cycle analysis in existing literature, but its efficacy in evaluating the lifetime costs and environmental impacts of infill materials remains unexplored. The current study presents a BIM-based approach for conducting LCC and LCA of infill materials, facilitating informed decision-making during the planning phase and promoting sustainable construction practices.

The purpose of this paper is to present the results of a two-year long study carried out in order to evaluate the corrosion performance of mild steel bare bars (BB) and epoxy-coated rebar (ECR) in concrete under a simulated harsh environment of chlorides.

The blocks are subjected to Southern Exposure testing. The electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and Tafel plot are performed to measure the polarization resistance and corrosion current densities of these rebars. Knife-peel test was performed to assess the adhesion between epoxy and underlying steel after two years of exposure.

Mild steel BB showed a high corrosion current density of 1.24 µA/ cm² in Tafel plots and a very low polarization resistance of 4.5 kΩ cm² in LPR technique, whereas very high charge transfer resistance of 1672 and 1675 kΩ cm² is observed on ECR and ECR with controlled damage (ECRCD), through EIS technique, respectively. EIS is observed to be a suitable tool to detect the defects in epoxy coatings. After two years of immersion in 3.89 percent NaCl⁻ solution, the mild steel BB were severely corroded and a considerable weight loss was observed, whereas under heavy chloride attack, ECR showed no deterioration of epoxy coating and neither any corrosion of underlying steel. Results of this study show that the durability of reinforced concrete (RC) structures with respect to corrosion could be enhanced by using ECR, especially in harsh climatic conditions.

The corrosion performance of mild steel and ECR in concrete under a simulating splash zone environment is evaluated. EIS was used to evaluate the health of epoxy and corrosion state of underneath steel rebars. EIS was able to detect the defects in epoxy. The durability of RC structures could be enhanced in harsh climate regions by using ECR.

This paper presents the details of a research study on developing composite masonry blocks using two types of mixes, conventional and lightweight mix, to enhance their fire/bushfire resistance and residual compressive strength.

Composite masonry blocks (390 × 190 × 90 mm) were fabricated using conventional cement–sand mix as the outer layer and lightweight cement–sand–diatomite mix as the inner layer. Material properties were determined, and all the mixes were proportioned by the absolute volume method. After 28 days of curing, density tests, compression tests before and after fire exposure and fire resistance tests of the developed blocks were conducted, and the results were compared with those of conventional cement–sand and cement–sand–diatomite blocks.

Developed composite blocks satisfy density and compressive strength requirements for loadbearing lightweight solid masonry units. Fire resistance of the composite block is –/120/120, and no cracks appeared on the ambient side surface of the block after 3 h of fire exposure. Residual strength of the composite block is higher compared to cement–sand and cement–sand–diatomite blocks and satisfies the loadbearing solid masonry unit strength requirements.

Composite block developed in this research can be suggested as a suitable loadbearing lightweight solid masonry block for several applications in buildings in bushfire prone areas.

Limited studies are available for composite masonry blocks in relation to their fire resistance and residual strength.

The purpose of this study is to explore the interfacial adhesion between superhydrophobic coatings FC-X (X = 1%, 2%, 3%, 4% and 5%) and the concrete substrate, along with the impact of FC-X on the water repellency characteristics of the concrete substrate.

One synthetic step was adopted to prepare novel F-SiO₂ NP hybrid fluororesin coating. The impact of varying mass fractions of F-SiO₂ NPs on the superhydrophobicity of FC-X was analyzed and subsequently confirmed through water contact angle (WCA) measurements. Superhydrophobic coatings were simply applied to the concrete substrate using a one-step spraying method. The interfacial adhesion between FC-X and the concrete substrate was analyzed using tape pasting tests and abrasion resistance measurements. The influence of FC-X on the water repellency of the concrete substrate was investigated through measurements of water absorption, impermeability and electric flux.

FC-4% exhibits excellent superhydrophobicity, with a WCA of 157.5° and a sliding angle of 2.3°. Compared to control sample, FC-X exhibits better properties, including chemical durability, wear resistance, adhesion strength, abrasion resistance, water resistance and impermeability.

This study offers a thorough investigation into the practical implications of enhancing the durability and water repellency of concrete substrates by using superhydrophobic coatings, particularly FC-4%, which demonstrates exceptional superhydrophobicity alongside remarkable chemical durability, wear resistance, adhesion strength, abrasion resistance, water resistance and impermeability.

Through the examination of the interfacial adhesion between FC-X and the concrete substrate, along with an assessment of FC-X’s impact on the water repellency of the concrete, this paper provides valuable insights into the practical application of superhydrophobic coatings in enhancing the durability and performance of concrete materials.

This paper aims to describe the application of several Six Sigma tools to explain the improvement changes needed in a company that manufactures concrete blocks. The paper explains the methodology and the tools of the Six Sigma system, their use in the project, the application of the DMAIC (Define, Measure, Analyse, Improve and Control) process for the identification and definition of the problems, the related performance variables and the results obtained.

The paper reports the research made to improve the production of concrete blocks, specifically, the application of the DMAIC process, which is part of the Six Sigma methodologies; DMAIC stands for Definition of the problem, Measurement of the performance, Analysis using specific statistical methods and tools, Improvement the factors that cause the problem and Control the processes to ensure that the problem will not occur again. Each of those steps is explained in detail in the paper, which also presents the application of other improvement techniques.

The results show the adaptability and relevance of Six Sigma for the improvement of production operations. It is clearly demonstrated that it leads to benefits such as the elimination of machine downtime, reduction of scrap from 18 to 2 per cent and the improvements made in plant layout and production facilities to increase the productivity.

In improvement projects, the differential between the initial and final conditions varies, depending on the magnitude of the problems or potential opportunities. Although this paper describes only the application of Six Sigma, the methodology has a wide potential application in most manufacturing industries.

With the Six Sigma and DMAIC tools’ application and the improvement process, the agility obtained is driving a more mechanized perspective of production operations. The customer service level was increased, through fast deliveries of complete orders. This project shows that the application of the Six Sigma methodology is feasible and produces attractive financial and operational results in this segment of the construction industry.

The companies dedicated to the production of concrete blocks commonly reproduce the systems and standards of the industry, which are commonly designed around civil engineering and technical issues. Thus, the application of improvement tools is exceptional in manufacturing environments. Although this paper is just one application of the methodology, it explains in detail the DMAIC use for companies that are committed to the development of new competencies to increase their competitiveness.

This study investigates the carbon footprint of the alternative structure types and materials used for the reconstruction of schools in Haiti. Are recycled construction materials more environmental than virgin materials? To estimate which alternative construction solution has the smallest carbon footprint, a survey was made for the school model used for the reconstruction programme in Haiti after the 2010 earthquake.

The carbon footprint was calculated using life cycle assessment methodology for five different concrete structure alternatives and five different cement mixes for the same design of a school building. In addition, the uptake of CO₂ through the carbonation of concrete during 50 years was calculated.

The carbon footprint of recycled materials can be either the best or worst option, depending on how the materials are used. The difference to using virgin materials is not big. This is mainly due to the lower structural performance of recycled materials, which needs to be compensated for by using additional reinforcements. Using cement mixes that have high amounts of substitutes for cement seems to lower the carbon footprint of structures considerably. The uptake of CO₂ in carbonation has potential but requires an optimal design and environment.

The findings give information for humanitarian project managers and designers on lowering the carbon footprint of their construction projects.

In many coastal areas where there are problematic soils, pavement construction on the soil is difficult because of the low shear strength and high consolidated. Also, given that the container terminals constitute more than 70% of the port area and as pavement in these areas is subject to heavy loads due to the long-term container storage, wheels of transport and movement equipment, the pavement must tolerate a distributed loading of at least 4 ton/m² in accordance with the type and weight of the containers imposed on the pavement. This study aims to investigate a variety of common pavement designs in coastal areas of southern Iran. The pavement type and characteristics of the subgrade layers are the same for each port; the thickness of different pavement layers is designed.

Due to problematic soil in the pavement subgrade, heavy and long-term container loading and the associated equipment, port pavement enjoys great importance.

The designed pavements are modeled by ABAQUS finite element software. The pavements are subject to a static load imposed by the corner casting container and resulted a distributed load 4 tons/m². The results from data analysis show that the concrete block pavements influenced by the containers static loads of 3%–20% have less vertical displacement on the subgrade than other pavements (rigid and flexible).

This paper is modeling 3 port pavement in Iran. Based on field evaluation and simulation actual loading on pavement.

From the 2000s onward, construction practices of urban residential buildings in China have shown a material transformation from clay brick to aerated concrete block. Moreover, the consumption of insulating materials for buildings has been increasing due to the new requirements in building energy-saving standards. This transformation and the increased consumption of insulating materials might have a vital impact on a building’s thermal comfort and its associated energy flows. Therefore, the purpose of this paper is to investigate the indoor thermal performance of urban residential buildings built with different materials and further discuss the correlations between indoor thermal comfort and the associated energy input.

This study investigated four residential buildings selected from four residential communities located in the cold climate zone of China. The Integrated Environment Solutions program was used to evaluate the thermal comfort levels and to quantify the operational energy consumption of the case study buildings. Additionally, the University of Bath’s Inventory of Carbon and Energy database was used to estimate the embodied energy consumption and CO₂ emissions.

The study found that materials transition and increasing consumption did not necessarily improve indoor thermal comfort. However, the materials transition has significantly decreased the embodied energy consumption of urban residential buildings. Furthermore, the increased utilization of insulating materials has also decreased the heating and cooling energy consumption. Therefore, overall, the environmental impacts of urban residential buildings have been reduced significantly.

In the future, residential buildings completed in the 1990s will need regular maintenance, such as adding insulation. Residential buildings completed based on the latest energy-saving requirements should optimize their ventilation design, for example, by increasing the ventilation rate and by reducing solar heat gains in the summer.

This paper investigates the effects of the materials change on thermal comfort levels and the environmental impacts of urban residential buildings in the cold climate zone of China, as these have not been the focus of many previous studies.