Abstract

In recent years, the use of granulated blast furnace slag (GBFS) sand as fine aggregate in concrete has been increasingly discussed from the viewpoint of environmental impact reduction and effective utilization of by-products in Japan. The various physical properties of concrete with GBFS sand, such as the compressive strength, drying shrinkage, and carbonation, were evaluated. Especially, it was demonstrated that GBFS sand can modify the hardened cement paste around it owing to the reaction of amorphous phase in the sand. Moreover, its resistance to sulfuric acid is considered to be as excellent as that of BFS powder. Therefore, in this study, we attempted to evaluate the performance of GBFS sand using a freeze-thaw (F-T) and acid immersion tests. Consequently, it was found that GBFS sand mortar had a significantly higher resistance to F-T and sulfuric acid than crushed sand mortar. In addition, it improved the resistance to freezing and thawing by prolonged curing. In our experiments, the resistance of GBFS sand mortar to sulfuric acid was measured to be approximately four times higher than that of crushed sand mortar. In contrast, in the case of nitric acid, the ratio was measured to be only two times higher. From the above results, it was concluded that the performance of GBFS sand can be easily judged by F-T and sulfuric acid immersion tests.

Abstract

In Africa, urban outdoor air pollution is responsible for an estimated 49,000 premature deaths annually with indoor use of solid fuels being responsible for eight times this value, the main burden being borne by Sub Saharan African countries. Air pollution, outdoor and indoor, affects the health and life chances of millions of people in Sub Saharan Africa (SSA)every day. There is a link between air pollution and poverty since poor people are exposed to higher concentrations of air pollutants and tend to suffer disproportionately from the effects of deteriorating air quality (AQ). Children in cities exposed to high concentrations of air pollutants will more often develop respiratory ailments which prevent them from developing and learning well. As a consequence they will suffer in adult life from low levels of qualifications and skills. The implication of poorly educated children is not only a reduction of quality of their lives but also an obstacle for the economic development of a country as a whole. Rapid urbanization means increase in motorization and economic activity which in turn leads to increased air pollution if countermeasures are not taken. In view these linkages addressing urban AQ in SSA is particularly important. Air pollution in Sub Saharan cities appears to be on the rise with respect to many key pollutants. In some cities where monitoring has been performed levels of air pollution exceed World Health Organization recommended guidelines. The main cause of urban air pollution is the use of fossil fuels in transport, power generation, industry and domestic sectors. In addition, the burning of firewood, agricultural and animal waste also contributes to pollution levels. Pollutant emissions have direct and indirect effects with a wide range of impacts on human health, ecosystems, agriculture and materials. There is a growing need to determine the state of urban AQ and the challenges posed to solve it and identify the most effective measures to protect human health and the environment. Learning from experience and successes in urban AQ management (AQM) from other countries can assists in the formulation and implementation of strategies to achieve better AQ in Sub Saharan Africa. This report compiles the information provided by the 25countries in a harmonized way and gives an in-depth review of AQ in SSA with AQ profile of each country, presenting the country's main current urban AQ issues, emissions standards, ongoing projects, lessons learned from good/bad practices. It was attempted to compile this information also for additional SSA countries from available publications and internet sources. Document type: Book

Abstract

In Africa, urban outdoor air pollution is responsible for an estimated 49,000 premature deaths annually with indoor use of solid fuels being responsible for eight times this value, the main burden being borne by Sub Saharan African countries. Air pollution, outdoor and indoor, affects the health and life chances of millions of people in Sub Saharan Africa (SSA)every day. There is a link between air pollution and poverty since poor people are exposed to higher concentrations of air pollutants and tend to suffer disproportionately from the effects of deteriorating air quality (AQ). Children in cities exposed to high concentrations of air pollutants will more often develop respiratory ailments which prevent them from developing and learning well. As a consequence they will suffer in adult life from low levels of qualifications and skills. The implication of poorly educated children is not only a reduction of quality of their lives but also an obstacle for the economic development of a country as a whole. Rapid urbanization means increase in motorization and economic activity which in turn leads to increased air pollution if countermeasures are not taken. In view these linkages addressing urban AQ in SSA is particularly important. Air pollution in Sub Saharan cities appears to be on the rise with respect to many key pollutants. In some cities where monitoring has been performed levels of air pollution exceed World Health Organization recommended guidelines. The main cause of urban air pollution is the use of fossil fuels in transport, power generation, industry and domestic sectors. In addition, the burning of firewood, agricultural and animal waste also contributes to pollution levels. Pollutant emissions have direct and indirect effects with a wide range of impacts on human health, ecosystems, agriculture and materials. There is a growing need to determine the state of urban AQ and the challenges posed to solve it and identify the most effective measures to protect human health and the environment. Learning from experience and successes in urban AQ management (AQM) from other countries can assists in the formulation and implementation of strategies to achieve better AQ in Sub Saharan Africa. This report compiles the information provided by the 25countries in a harmonized way and gives an in-depth review of AQ in SSA with AQ profile of each country, presenting the country's main current urban AQ issues, emissions standards, ongoing projects, lessons learned from good/bad practices. It was attempted to compile this information also for additional SSA countries from available publications and internet sources.