It is the most important issue for the sustainable society to reduce output as disposal and input of natural resource. This paper shows directions of how to reduce the output from public works and the input for public works.The directions are how to select good ways from various type of recycling. The first is to check from view point of the output of society. The second is to check from view point of the input of society.According to the directions, we found some recycling ways cause increase of the input and/or the output.
disposal, and use of natural resources. In order to apply CO 2 emission data estimated with this LCA method to decision-making, we must first determine the difference between the predicted value (at the design stage) and the definitive value (after the completion of construction) .Results and Discussion. The difference between the predicted value and the definitive value is due to (1) changes in the types and quantities of construction material and the machinery specified in the design documents, and (2) updating the environmental load units during the construction process. To examine (1) , CO 2 emissions were calculated on the basis of seven design documents. These documents focused on roads, bridges, tunnels, etc. The results of the calculations showed the following: 1) the predictive value is likely to range between 76% and 164%; 2) the main factors responsible for fluctuations in the predictive value are transportation distance and type of construction machinery; 3) excluding the influence of transportation distance and type of construction machinery, the predictive value is likely to range between 87% and 108%.Regarding (2) , we think that the value of the environmental load units of concrete, iron, and asphalt may vary drastically.Conclusions. This study showed that differences exist between predicted values and definitive values in the LCA method for infrastructures. When making decisions based on a predicted value, we must take this difference sufficiently into account.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.