| In order to develop infrastructure systems, people may inadvertently destroy environmental resources on which their societies depend. To maintain economic development, it is necessary to develop adequate infrastructure systems, yet these systems may have negative impact on environmental conservation, such as deforestation and habitat destruction, climate changes, increased emission of CO2, human population growth, or war, etc. Therefore, it is necessary to balance these two important issues: the environment on which a society depends; and the infrastructure systems which are necessary for economic growth.; In this research, one of green materials has been added into concrete. The green material, rice husk ash (RHA), is a by-product from rice production. It is rich in silica (about 85% to 90% by weight). During the milling of a rice paddy, rice broken and bran constitute about 78% of total weight, and the remaining 22% is husk. For every 1,000 kg of paddy milled, about 55 kg of RHA is generated. Recent research has shown that by replacing 10% of the cement in concrete by RHA, compressive strength can be increased up to 30% and water permeability can be reduced by up to 60%. In this research we studied the environmental sustainability impacts of RHA as a green material on high temperature resistance of concrete.; To improve concrete-based infrastructures exposure to high temperature, polypropylene (PP) fibers have been also added into concrete. The spalling damage, the residual strength, and recovery strength of the concrete were tested systematically. The results are important for the evaluation of the effect of RHA and PP fibers on fire resistance of the concrete.; Then, life cycle assessment is applied to see the sustainability of infrastructure development. Sustainability is a complex subject that in general can be considered as three types: institutional, economic and financial, and ecological. In the contest of economic growth, environment issues are generally considered secondary. Is it required that these two goals always be in conflict? We think not, and this thesis presents one case study where aspects of the two can work in harmony.; In Appendix C, it is a study for alkali aggregate reaction (AAR). This is a under going project funded by Tokyo Electric Power Company, Tokyo, Japan. |
