Experimental Studies on Green Concrete using Volcanic Ash and PVA/VE

This paper investigates the influence of volcanic ash (VA) and vinyl acetate/ethylene copolymer powder (PVA/VE) as partial cement replacement on the engineering properties of blended binders concretes. The parameters studied included density, workability and compressive strength. A total number of 12 trial mixtures were prepared and tested by varying the proportions of binders. Firstly, VA was used to replace OPC at dosage levels of 5%, 10%, 15%, 20%, 25%, and 50% by weight of the binder. Secondly, PVA/VE was used to replace OPC at dosage levels of 0.5%, 1%, 1.5%, 2% and 2.50% by weight of the binder. Finally, the optimum replacement levels of VA and PVA/VE were determined and used to prepare a new trial mix. The results show that cement replacement up to 15% volcanic ash and 1.5% PVE/VE leads to increase in workability and compressive strength for C30 grade compared with the control mixture. Keywords: Green concrete, Compressive strength, Workability, Volcanic ash, PVA/VE

Effect of Particle Sizes on Mechanical Properties of Concrete Containing Crumb Rubber

This paper investigates the mechanical properties of concrete containing different particle sizes of crumb rubber. This research have been conducted on 10% replacement of fine aggregates by three different particle sizes of crumb rubber which are 1 mm crumb rubber, 0.4–1 mm fine dust crumb rubber, and 0.2–0.6 mm powder crumb rubber. Laboratory tests include slump test, compressive test, flexural test, bulk density test, water absorption test, porosity test, and ultrasonic pulse velocity (UPV) test were conducted on the concrete mixes. All concrete specimens were tested at the age of 7, 14, 28, and 56 days. The results from laboratory testing on concrete specimens were analyzed. It was found that in the inclusion of crumb rubber into concrete, it will reduce the strength of concrete. The usage of greater particle sizes of crumb rubber which is 1 mm crumb rubber gives better strength of concrete compared to the usage of smaller particle sizes of crumb rubber which is 0.2–0.6 mm powder crumb rubber. Therefore, the rubberized concrete can absorb the impact energy and suitable usage in roads and highways construction such as road divider, road pavement, and others because it can absorb impact from vehicles load, disaster and others. Keywords: Crumb rubber, Workability, Concrete strengt

An Assessment of the Impacts of Construction Projects on the Environment in the Gaza Strip

The aim of this study is to assess the most common impacts of construction projects on the environment in the Gaza Strip and propose the best solutions in curbing down the adverse impacts. To achieve this aim, a structured survey, in the form of a questionnaire was conducted to identify the most critical and important impacts of construction projects on the environment. Environmental impacts were categorized into three safeguard subjects: ecosystems, natural resources, and public impacts. The results showed that dust generation, noise pollution, operations with vegetation removal, and air pollution are the most significant environmental impacts of construction sites in the Gaza Strip. In addition, the public impacts are the most important category that affects the environment in the Gaza Strip. Furthermore, the results demonstrated that the necessity of taking measures to protect labors and residents who are living near to construction sites. It is recommended to enhance the knowledge and awareness of construction participants to the environmental impacts of construction projects and enact strict laws to curb down the adverse impacts of construction projects. In addition, the researchers should look for alternative methods for construction to mitigate the adverse impacts of construction projects on the environment. The results of this study can help decision makers to identify major construction impacts on the environment and make environmentally friendly construction plans in the early stages of construction. Keywords: Environment, Construction projects, EIA, Gaza Strip