S. S. G. Hashemi - Academia.edu (original) (raw)

Papers by S. S. G. Hashemi

Research paper thumbnail of Microstructural characterization and mechanical properties of bottom ash mortar

Coal Bottom Ash (CBA) is one of the widely-produced residues of coal incineration in thermal powe... more Coal Bottom Ash (CBA) is one of the widely-produced residues of coal incineration in thermal power plants. The annual extraction of such a huge amount of waste needs a massive transfer field, which constitutes a threat to the environment. However, the utilization of such residue as a fine aggregate in concrete can be an environmentally-friendly opportunity. Hence, the main purpose of this paper is to evaluate the microstructure and mechanical properties of the usage of BA as a fine aggregate replacement in mortar mixtures. It is observed that BA has a reactive fraction with pozzolanic characteristics. This provides stronger mortar when a medium volume of the material (up to 40%) is substituted. In addition, the CBA based mixture can be classified as lightweight concrete. The compressive strength value of the specimen using 40% CBA at 56 days was 55 MPa, which reached the same strength limit of control mortar mixture.

Research paper thumbnail of Safe disposal of coal bottom ash by solidification and stabilization techniques

h i g h l i g h t s Solidification and stabilization of coal bottom ash waste (CBA) using CEM1 as... more h i g h l i g h t s Solidification and stabilization of coal bottom ash waste (CBA) using CEM1 as the binder have been evaluated. Toxic elements can be immobilized successfully to nearly zero even in the case of a low CEM1 content. Based on leaching and compressive strength results, CEM1/CBA mixtures can be considered for the construction industry. a b s t r a c t Solidification and stabilization of coal bottom ash waste (CBA) using CEM1 as the binder have been evaluated in case of leaching as well as the possibility to use this mixture for the construction industry. For this, the CEM1/CBA mass ratio has been varied between 0.5 and 2 and heavy metals leaching of Cu, Cd, Ni and Pb evaluated. Two types of crushed block and whole block leaching tests have been conducted to determine the leaching properties of deionized water, acetic acid and nitric acid leachates. It has been demonstrated that all elements can be immobilized successfully to nearly zero even in the case of a low CEM1 content. Furthermore, it has been shown that more heavy metals leached from the matrix when acetic acid used compared to other leachates. Next to this, the mechanical properties have been tested. After 56 days a compressive strength between 25 and 40 MPa has been measured from 0.5 to 2 CEM1/CBA mass ratios. Based on leaching and compressive strength results, CEM1/CBA mixtures can be considered for the construction industry.

Research paper thumbnail of Performance of green roofs with respect to water quality and reduction of energy consumption in tropics: A review

Green roofs are an increasingly important component of water-sensitive urban design systems that ... more Green roofs are an increasingly important component of water-sensitive urban design systems that can potentially improve the quality of urban runoff, reduce the energy consumption of buildings, and add esthetic value to the environment. The most important green roof abilities, which appear as a key feature in urban catchments are the ability of rainwater detention and retention and reduction in energy consumption. This paper aims to provide an overview of the effects of the application of the green roof strategy on the quality of runoff water and the reduction of energy consumption. The components of a green roof are discussed, and the advantages and disadvantages of different types of green roofs are assessed. In addition, the origins and concentrations of the main pollutants are discussed, moreover environmental cost-benefits of green roofs are also considered. In addition, the main factors that affect the quality of green roof runoff water, e.g., plant species, fertilization, pH, growth media as well as how green roofs could reduce energy consumption are discussed. Green roofs are considered as sustainable approach for runoff management with achieved aesthetical values and in combination with energy saving on heating/cooling. Hence, green roof causes a sufficient decrease in energy consumption and consequently in the related energy costs. It can help to improve the micro climate around the buildings and save money and also improve water quality. Therefore, green roofs may turn into a profitable investment. Some recommendations for future study also are proposed.

Research paper thumbnail of Microstructural characterization and mechanical properties of bottom ash mortar

Coal Bottom Ash (CBA) is one of the widely-produced residues of coal incineration in thermal powe... more Coal Bottom Ash (CBA) is one of the widely-produced residues of coal incineration in thermal power plants. The annual extraction of such a huge amount of waste needs a massive transfer field, which constitutes a threat to the environment. However, the utilization of such residue as a fine aggregate in concrete can be an environmentally-friendly opportunity. Hence, the main purpose of this paper is to evaluate the microstructure and mechanical properties of the usage of BA as a fine aggregate replacement in mortar mixtures. It is observed that BA has a reactive fraction with pozzolanic characteristics. This provides stronger mortar when a medium volume of the material (up to 40%) is substituted. In addition, the CBA based mixture can be classified as lightweight concrete. The compressive strength value of the specimen using 40% CBA at 56 days was 55 MPa, which reached the same strength limit of control mortar mixture.

Research paper thumbnail of Safe disposal of coal bottom ash by solidification and stabilization techniques

h i g h l i g h t s Solidification and stabilization of coal bottom ash waste (CBA) using CEM1 as... more h i g h l i g h t s Solidification and stabilization of coal bottom ash waste (CBA) using CEM1 as the binder have been evaluated. Toxic elements can be immobilized successfully to nearly zero even in the case of a low CEM1 content. Based on leaching and compressive strength results, CEM1/CBA mixtures can be considered for the construction industry. a b s t r a c t Solidification and stabilization of coal bottom ash waste (CBA) using CEM1 as the binder have been evaluated in case of leaching as well as the possibility to use this mixture for the construction industry. For this, the CEM1/CBA mass ratio has been varied between 0.5 and 2 and heavy metals leaching of Cu, Cd, Ni and Pb evaluated. Two types of crushed block and whole block leaching tests have been conducted to determine the leaching properties of deionized water, acetic acid and nitric acid leachates. It has been demonstrated that all elements can be immobilized successfully to nearly zero even in the case of a low CEM1 content. Furthermore, it has been shown that more heavy metals leached from the matrix when acetic acid used compared to other leachates. Next to this, the mechanical properties have been tested. After 56 days a compressive strength between 25 and 40 MPa has been measured from 0.5 to 2 CEM1/CBA mass ratios. Based on leaching and compressive strength results, CEM1/CBA mixtures can be considered for the construction industry.

Research paper thumbnail of Performance of green roofs with respect to water quality and reduction of energy consumption in tropics: A review

Green roofs are an increasingly important component of water-sensitive urban design systems that ... more Green roofs are an increasingly important component of water-sensitive urban design systems that can potentially improve the quality of urban runoff, reduce the energy consumption of buildings, and add esthetic value to the environment. The most important green roof abilities, which appear as a key feature in urban catchments are the ability of rainwater detention and retention and reduction in energy consumption. This paper aims to provide an overview of the effects of the application of the green roof strategy on the quality of runoff water and the reduction of energy consumption. The components of a green roof are discussed, and the advantages and disadvantages of different types of green roofs are assessed. In addition, the origins and concentrations of the main pollutants are discussed, moreover environmental cost-benefits of green roofs are also considered. In addition, the main factors that affect the quality of green roof runoff water, e.g., plant species, fertilization, pH, growth media as well as how green roofs could reduce energy consumption are discussed. Green roofs are considered as sustainable approach for runoff management with achieved aesthetical values and in combination with energy saving on heating/cooling. Hence, green roof causes a sufficient decrease in energy consumption and consequently in the related energy costs. It can help to improve the micro climate around the buildings and save money and also improve water quality. Therefore, green roofs may turn into a profitable investment. Some recommendations for future study also are proposed.