Determinants of sustainable building materials (SBM) selection on construction projects

The complexity and fragmented nature and the multiple stakeholders in the construction industry often make it difficult to come up with a firm decision regarding sustainable building materials selection. The wrong choice could negatively impact the project objective and performance outcome. This study assessed the critical factor influencing the choice of sustainable building materials (SBM) selection on construction projects in the Southeast geopolitical zone of Nigeria. Data were collected using a well-structured questionnaire, non-probability (purposive and snowball) sampling techniques, and an internet-mediated survey. Data analyses were carried out using the appropriate descriptive and inferential statistical tools and exploratory factor analysis (EFA). The study revealed recycled plastic, natural clay and mud, stone, bricks and tile, cellulose, stray bales, grasses, limestone, and wood timber, are the commonly used sustainable building materials. Also, their level of awareness is high while their adoption is moderate. EFA revealed that the major clusters of determinants of the choice of green building materials are: emissions minimisation, low running cost and reusability, low thermal and energy consumption efficiency, low cost and high health and safety consideration and waste minimisation. The key factors influencing the choice of sustainable building materials selection in construction are: reducing greenhouse gas emissions from buildings, materially embodied energy cost, operating and maintenance costs, non-toxic or low toxic emissions generated by the products/materials, recyclability of the building materials, availability of the technical skills, renewable (reusable) properties, inhibiting the impact of buildings on the environment, safety and health of the occupants, and appearance and aesthetic. It is recommended that consideration be given to these factors in selecting sustainable/green building materials in the designs and specifications of construction projects.

EXPLORING GREEN FEATURES THAT MAKE BUILDING MATERIALS GREEN

The construction industry plays a significant role in the economic growth of a country. Nevertheless, the construction industry has created severe adverse environmental impacts. Therefore, green building technologies are implemented to alleviate the adverse effects of the construction industry. Using green materials instead of conventional building materials with high environmental impacts has been identified as one such implementation. However, there seems to be much confusion in defining green building materials. Hence, it is vital to explore the features of green building materials. Therefore, this article investigates green features that qualify the building materials as green building materials. A qualitative research approach was selected as the research methodology, and semi-structured interviews were conducted with seven green building experts. The data was analysed using content analysis. Findings revealed that recycled content, local availability of materials, embodied energy of materials, use of rapidly renewable material, usage of waste material for the production process, material wastage content in the production process and pollution prevention in the production process are the green features. The study results guide the identification of green building materials that can replace the materials with poor environmental sustainability.

Green Building Materials Based on Waste Filler and Binder

This study is aimed at the application of alternative binder (AB) into bio-aggregate-based composite. The technically important parameters (density, thermal conductivity, water absorption and compressive strength) of 28, 60 and 90 days hardened green composites containing chemically and physico-chemically modified hemp hurds (HH) with AB compared to the Portland cement (PC) are presented. Testing of two reference bio-composites with original HH confirmed higher values of compressive strength and thermal conductivity unlike water absorption for all hardened specimens based on alternative binder (MgO-cement) compared to conventional PC. Changes in the final properties of hardened bio-composites were affected by treatment process of organic filler and alkaline nature of MgO-cement. The combination of purified HH by ultrasound treatment and AB appears to be promising for preparation of bio-based composite material with better properties compared to PC. In this paper, other option of the preparation of bio-composite system based on original (non-treated) filler and binder consisting of optimal activated MgO and silica fume is presented.

Assessment of Green Building Materials’ Attributes to Achieve Sustainable Building Façades Using AHP

The need to enhance the performance of building façades and mitigate adverse environmental impacts has promoted the hypothesis of integrating green materials towards sustainable buildings. Façade designers tend to select building materials based on their green characteristics (origin) or green performance; however, this study highlights the importance of integrating both into the decision process. The main objective is to develop a new assessment process for selecting green building façade materials based on green performance and green originality. Furthermore, the evaluation framework considers four green building rating systems as a reference to allocate credits for the relevant criteria. Applying the proposed criteria in this study helps maximize the points for accreditation when incorporating green building materials in building façades. Moreover, the Analytic Hierarchy Process (AHP) is used to assign the proposed criteria’s weighting importance based on the four rating systems’ average points. After that, performing sensitivity analysis to identify each criterion’s influence is conducted. The study concluded that involving minimum levels of adverse impacts is the preferable criteria regarding the green origin concept. As for the green performance, promoting the performance of indoor air quality is the most favorable selection criteria.

Simulation of Green Building Materials Uses and its Environmental Impacts: Case of Jordan

Construction is one of the most important factors affecting the environment such as global warming and carbon dioxide emissions. In addition, it represents 40% of the consumption of energy resources around the world. Jordan is one of the countries that suffer greatly from this aspect. In this research, a simulation was conducted of a multi-use building located in a university in Jordan using the ArchiCAD program, which helps us to accurately determine the construction location and obtain the results of materials and strategies that were applied to the building. Thermal insulation materials were used to show the effectiveness of their impact on the temperature difference per unit of heat flux needed to sustain one unit of heat flux (R-value) for the building. Shading means were also applied to the building’s glass facades that reduce heat loads and help the heating, ventilation, and air conditioning (HVAC) system inside the building. Finally, it was shown the difference in the environmental impact of a building that uses 100% solar energy and emits zero CO2 emissions. While a building that uses 50% solar energy and 50% oil energy emits a high amount of CO2. It becomes clear that the increasing use of green building tools helps greatly in facing the problems of the environment and the consumption of energy resources.

Optimal Mix Ratios of Green Building Materials and Construction Cost Control

Green concrete wall-building composite materials (namely GBMs, green building materials for short) have superior mechanical properties and good durability, thus they are now a high-profile topic in relevant research field. However, due to the existence of risk factors such as the high initial cost, and unclear policy direction, the promotion of GBMs has been greatly limited. In this context, it is a necessary work to study the cost control of construction projects, and figure out the relationship between the saving of building operating cost and the increase of initial construction cost. For this purpose, this study experimented on the optimal mix ratios of GBMs to control the construction budget of engineering projects. At first, this paper modeled the strain-hardening and steady-state cracking of GBMs, and constrained the models based on the bridging rule, the energy criterion, and the strength criterion. Then, this paper constructed a fractal model for the dense effect of powder particles in the aggregates of the GBMs, and analyzed its fractal features; after that, this paper designed the mix ratios of GBMs and experimented on the mechanical properties; at last, this paper constructed a production cost-use benefit model of the GBMs, completed the construction budget control of the engineering project, and gave experimental results of the performance of GBMs and the use cost calculation and analysis results.