Prediction of the volume of waste concrete from demolished highway bridges and the effect of life-lengthening on reduction in the volume of waste concrete in Miyazaki Prefecture

摘要

To predict the volume of waste concrete from demolished highway bridges and evaluate the effect of life-lengthening on reduction in the volume of waste concrete, constructed and demolished bridges in Miyazaki Prefecture were investigated. Normal distribution and Weibull distribution were considered as the life distribution of the bridges and the parameters of the distributions were determined to meet the observed and calculated number of demolished bridges. There were distributions available for estimating the number of demolished bridges. The mean life estimated was 61 years in normal distribution and 69 years in Weibull distribution. Furthermore, distributions were also available for estimating the volume of waste concrete of demolished bridges. These distributions predict that the volume of waste concrete will increase almost linearly by 2100, and if the mean life is extended by 10 years, the accumulated volume of waste concrete will be reduced by 10～20%.