Mohammed Al-Humaiqani

The frequency and severity of climate change are projected to increase, leading to more disasters, increased built environment system (BES) vulnerability, and decreased coping capacity. Achieving resilience objectives in the built environment is challenging and requires the collaboration of all relevant sectors and professionals. In this study, various stakeholders were engaged, including governmental authorities, regulatory bodies, engineering firms, professionals, contractors, and non-governmental and non-profit organizations (NGOs and NPOs, respectively). The engagement was carried out through the answering of a questionnaire survey that reflects their perceptions about climate change adaptation, the built environment resilience qualities (RQs), and the degree of resilience of the existing built environment and their perceived capacities. The results were analyzed using several statistical tests. The results revealed that advancing public understanding and management tools, reduc...

The frequency and severity of climate change are projected to increase, leading to more disasters, increased built environment system (BES) vulnerability, and decreased coping capacity. Achieving resilience objectives in the built environment is challenging and requires the collaboration of all relevant sectors and professionals. In this study, various stakeholders were engaged, including governmental authorities, regulatory bodies, engineering firms, professionals, contractors, and non-governmental and non-profit organizations (NGOs and NPOs, respectively). The engagement was carried out through the answering of a questionnaire survey that reflects their perceptions about climate change adaptation, the built environment resilience qualities (RQs), and the degree of resilience of the existing built environment and their perceived capacities. The results were analyzed using several statistical tests. The results revealed that advancing public understanding and management tools, reducing economic losses, and developing necessary plans still require improvement. Additionally, the BESs were ranked concerning accepting the change and uncertainty inherited from the past or generated over time. This study emphasized the perception that the decision-making domain is crucial for delivering a reflective built environment. Additionally, features such as advancing public understanding and management tools, reducing economic losses, and developing necessary plans still require improvement. Furthermore, there is a belief in the importance of the task forces within the community as part of an emergency response plan, and a less reflective system would have less recovery speed. Therefore, the rapidity characteristic of a built environmental system to accept the change and uncertainty inherited from the past or generated over time is correlated to the system’s reflectivity quality. This study emphasizes the significant correlation between the different RQ traits. It also encourages researchers to formulate more objective methods to reach a set form for measuring RQs as an engineering standard.

Abstract This paper examines the relation between strength and elastic modulus of high performance concrete (HPC) tailored from various heavy and normal weight aggregates coupled with the effect of micro-silica as a supplementary cementitious material (SCM). Elastic modulus of concrete is an important mechanical property and plays an important role for the calculation of deformations in the structural components. Experimentation was conducted in precise laboratory environment and all other parameters were kept constant in the mixtures. This investigation was prompted to supply the construction industry with appropriate information on how specific properties of HPC mixtures can be improved using local normal and heavy weight aggregates and incorporating supplementary cementitious materials. In other words, this paper will encourage the local aggregate consumption in mega projects that to be constructed for special purposes. In this investigation, dissimilar types of normal and heavy weight coarse aggregates were used. It was found that it is worthy to study experimentally the relation between strength and MOE of HPC when different types of coarse aggregates are used for an indicated HPC mixture with a corresponding combination of supplementary cementitious material. The comparison of experiment results with the ACI prediction models showed that the models should be enhanced for accurate prediction for the effect of aggregate type with and without the use of micro-silica as supplementary cementitious material. An assessment of the need for an aggregate and micro-silica based modification to the ACI models is also proposed. The experimental work conducted in this investigation confirmed that the type of aggregate and its combination with a supplementary cementitious material would have important influence on the HPC characteristics. Hence, the use of appropriate values for the strength-MOE relation for a HPC mixture based on the nature of used aggregates and SCM is recommended. However, such values might be not available in some cases, if so the experimental trend lines presented in this study can be used to calculate them.

The exposure of built environment systems to climate-related disturbances increases over time. As such, the resilience of the built environment against climate change shocks and stresses has increasingly become a concern on the local, national, and global levels. Therefore, there is a need to measure the impact, build coping and adaptive capacities, and improve the functionality of the vulnerable systems. In addition, the systems must adopt the minimum resilience functioning methods and practices. Hence, this paper reviewed the most common resilience qualities (RQs), capacities, and dimensions of the built environment and their interdependencies. The research method is based on analyzing the relevant peer-reviewed journal papers published in renowned international journal papers and databases during the past two decades. The scope of the study is narrowed down by following specific guidelines to ensure a proper selection of up-to-date research articles to provide a precise understanding of the research progress on the built environment RQs. It provides an overview of the different definitions and indicators in which RQs have been applied to built environment planning, analysis, and design, emphasizing the various dimensions and relevant capacities. The study concludes that integrated resilience indicators, planning, and design methodology are crucial for incorporating RQs into the framework that influences the built environment. The built environment RQs demonstrated by this study include reflectivity (Rf), robustness (Rb), redundancy (Rd), flexibility (Fx), resourcefulness (Rs), rapidity (Rp), inclusivity (Ic), and integration (It). Nevertheless, the built environment RQs are still growing, requiring further study to develop plans and policies for effective and timely responses to climate change effects.

This paper presents an experimental study on the gamma ray radiation shielding properties of normal and heavy high performance concretes (HPCs). HPCs were produced with different low water-to-cementitious materials ratios (w/cm) and tested for 0.663 MeV γ-rays energy of 137Cs radioactive using NaI(Tl) scintillation detector. It was observed in this research that the compressive strength of heavy HPCs plays an important role in enhancing the attenuation of gamma rays. The compressive strength and attenuation of gamma rays in heavy weight HPCs have a near to linear relation. On the other hand, it was also found that the compressive strength of the normal concrete has almost no effect on the attenuation of gamma rays. The Linear and mass attenuation coefficients were calculated and compared with the past research and a good agreement has been found. However, the HPCs density considerably affects the attenuation of gamma rays. With the increase in the density, the attenuation coefficients increases linearly. This endorse that the relationship between the HPC density and the gamma attenuation coefficients is linear.

h i g h l i g h t s Strength and MOE of HPC from heavy and normal weight aggregates coupled with micro-silica. Requirement for construction projects to use locally available building materials. Comparison of experiment results with ACI prediction models enhanced for accurate prediction. a b s t r a c t This paper examines the relation between strength and elastic modulus of high performance concrete (HPC) tailored from various heavy and normal weight aggregates coupled with the effect of micro-silica as a supplementary cementitious material (SCM). Elastic modulus of concrete is an important mechanical property and plays an important role for the calculation of deformations in the structural components. Experimentation was conducted in precise laboratory environment and all other parameters were kept constant in the mixtures. This investigation was prompted to supply the construction industry with appropriate information on how specific properties of HPC mixtures can be improved using local normal and heavy weight aggregates and incorporating supplementary cementitious materials. In other words, this paper will encourage the local aggregate consumption in mega projects that to be constructed for special purposes. In this investigation, dissimilar types of normal and heavy weight coarse aggregates were used. It was found that it is worthy to study experimentally the relation between strength and MOE of HPC when different types of coarse aggregates are used for an indicated HPC mixture with a corresponding combination of supplementary cementitious material. The comparison of experiment results with the ACI prediction models showed that the models should be enhanced for accurate prediction for the effect of aggregate type with and without the use of micro-silica as supplementary cementitious material. An assessment of the need for an aggregate and micro-silica based modification to the ACI models is also proposed. The experimental work conducted in this investigation confirmed that the type of aggregate and its combination with a supplementary cementitious material would have important influence on the HPC characteristics. Hence, the use of appropriate values for the strength-MOE relation for a HPC mixture based on the nature of used aggregates and SCM is recommended. However, such values might be not available in some cases, if so the experimental trend lines presented in this study can be used to calculate them.