Journal of Civil Engineering Beyond Limits (CEBEL)

Vinayak Kaushal Mohammad Najafi

Coronavirus disease 2019 (COVID-19) is a respiratory illness caused by a virus called SARS-CoV-2. With the global spread of COVID-19, there is a compelling need to improve the health and safety of workers employed in the construction projects (CP). Occupational characteristics, such as interfacing with the public and being in close quarters with other workers, not only put workers at high risk for disease, but also make them a nexus of disease transmission to the community. The objectives of this study are: (1) to evaluate the implications of COVID-19 pandemic on health and safety of workers in construction industry (CI), (2) to analyze the socio-economic-environmental impacts of the pandemic on construction, and (3) to recommend effective ten-point strategy to reduce COVID-19 impacts on the health of construction workers in CP. The required information is collected and analyzed based on the recently published literature, interviews, surveys, and industry experiences. The results reveal that hours of work, wages, workload and stress levels, access to paid leave, interactions with co-workers and supervisors, and health-promoting workplaces have major impacts on the well-being of workers, their families, and their communities. This study will be helpful for the owners, contractors, project managers and owners, and governmental authorities in adopting the effective strategies to improve the health and safety of workers as well as productivity and efficiency in construction projects.

https://doi.org/10.36937/cebel.2021.002.001

Nwzad abdulla

Confinement of concrete columns can be an effective means of enhancing structural members' deformation—alternative materials such as uPVC tube show elastic-plastic behavior with considerable elongations at failure. The material ductility features significant deformations that usually considered to be belonging to the set of mechanical properties. The tube can be applied for encasing concrete, thereby influencing the deformability capacity of a column. The current work aims to evaluate the axial strain of plastic tubes with concrete-infill (PTCI) specimens tested under uniaxial compression load. A strain model was developed for PTCI specimens using a normalized confinement stiffness procedure, based on a database of experimental results from recent studies 2019-2020 and those of the present study. Five existing FRP-confined concrete models and the developed model were employed to predict PTCI columns' strain, and the predictions were compared with experimental results in the database. Three statistical indexes were used to evaluate the proposed and the three existing FRP-confined concrete strain models' performance. The indexes included: Average absolute relative error (AAE), Normalized root-mean-square error (NRMSE), and coefficient of correlation (R2). The comparison shows the proposed model to give more close prediction to the experimental test data and the comprehensive database to yield the lowest average absolute error (AAE), and root mean square error (RMSE) compared with other models in the present study.

https://doi.org/10.36937/cebel.2021.002.002

Nima Norouzi Maryam Fani Zahra Nasiri

The concept of green architecture, also known as "sustainable development" or "green building," is the theory, science, and style of buildings designed and built based on environmentally friendly principles. Green architecture seeks to minimize the number of resources used in the construction, operation, and management of the building and limit the damage caused to the environment by spreading, pollution, and waste of building components. New water and materials are used to design, build, operate and conserve building energy and generate large amounts of waste that negatively affect health and the environment. To limit these effects and design environmentally sound and resource-efficient buildings, the concept of "green building systems" needs to be introduced, clarified and understood, and practiced. One of the solutions is to use green building methods in the construction industry in today's world. Demand for sustainability as a definitive solution to all environmental challenges Inspired by this research to emphasize the priority of increasing sustainable environmental productivity to reduce carbon emissions to discuss and demonstrate sustainable buildings in Iran (new and existing) and Presenting the principles of energy audit used in them and their performance toward standards. Meanwhile, Iran is ranked as one of the good countries in building growth and green energy in the Middle East and other countries, according to the US Green Building Council's ranking of energy consumption, renewable energy, and recycled materials in 2015-2016.

https://doi.org/10.36937/cebel.2021.002.003

Michael Tiza

This study reviews relevant literature on the characterization of reclaimed asphalt pavement(RAP) and its interaction with polymer modified asphalt(PMA). The study on fatigue cracking indicates that several indexes of binder performance showed that the use of recovered RAP binder usually decreased Polymer Modified Asphalt(PMA) binder tolerance to cracking. RAP binding rigidity has affected fatigue tolerance of the PMA binder. The greater the rigidity of the RAP binder, the more fatigue strength the binders would provide. In addition, several researchers demonstrated that the RAP binder the elastomeric response quality. It was generally found that the RAP binder effect on the PMA binder is similar to the unmodified binder effect. The resistance to rutting in the PMA binder had improved and fatigue cracking and thermal cracking minimized. Moreover, several researchers found that the inclusion of a RAP lowers elastomeric efficiency. In all, RAP binding stiffness and RAP gradation are essential features for proper RAP-containing PMA-mix designs. During RAP binder characterization, the mortar testing process without the use of binder extraction proved to be more effective than the conventional method as per review. Also, the best measure for the evaluation of the fatigue cracking efficiency of RAP containing PMA blends does not seem to have any consensus among researchers as several researchers seem to have varying experimental facts. The literature on Life Cycle Analysis was also reviewed.

https://doi.org/10.36937/cebel.2021.002.004

Engin Yener Ali Khanjarkhani Rüstem Gül

Structural lightweight concretes have the potential to be used in road pavements and bridge decks due to their properties such as sufficient wear resistance, high impermeability, superior freeze-thaw resistance and ductile behavior. However, road pavements are directly exposed to nitric acid and sulfuric acid solutions created by the exhaust gases of transportation vehicles in humid environments. Therefore, the concrete to be used in road pavements must be resistant to these acid effects. In addition, sufficient strength must be guaranteed when used as pavement material. The aim of this study is to produce lightweight concrete suitable for road pavements and other structures exposed to acid effects. For this, the effect of silica fume (SF) and fly ash (FA) on acid resistance and strength development of lightweight concrete with perlite aggregates was investigated. Five different lightweight concrete mixtures were produced by substituting 0%, 5%SF, 10% SF, 10%FA, 20% FA instead of cement by weight. Natural perlite rock has been used as an aggregate source in order to provide high strength and lightness. The cylindrical samples produced were kept in lime saturated water cure for 120 days and their compressive strength was measured on the 28th, 56th, 90th and 120th days. In addition, in order to monitor the acid resistance, the strength changes of the samples exposed to 5% sulfuric acid and 5% nitric acid solution after 28 days of standard curing were followed until the 120th day. Results show that, SF and FA additives increase the compressive strength especially at older ages. In case of 10% SF, the 120-day strength value increased by 18.6% and reached 34.5 MPa. Also, lightweight perlite concrete is highly resistant to nitric acid and sulfuric acid effects. In the case of 92 days of nitric acid and sulfuric acid exposure, the strength losses are only 5.2% and 13.4%, respectively. In order to fully benefit from SF and FA, concretes must be adequately cured before acid attack. It has been concluded that it is possible to produce high-strength and acid-resistant lightweight concretes suitable for road pavements and many other structural elements by using natural perlite aggregate.

https://doi.org/10.36937/cebel.2021.002.005