Composition of demolition wastes from Chi-Chi earthquake-damaged structures and the properties of their inert materials

Abstract

The disastrous Chi-Chi earthquake struck Taiwan on 21 September 1999 and resulted in the creation of more than 20 million cubic metres of demolition waste, which was stored temporarily at several sites. To reduce the site clearing costs, the inert materials (concrete, brick, pottery, and fines) in the wastes should be reclaimed and recycled immediately; but most of their properties were not known. Therefore, this study investigates the properties of demolition wastes, including inert materials, coarse portions, and fines obtained from two earthquake demolition waste storage sites (Puli and Tali) and one normal urban construction waste storage site (Taichung). It is found that the volumetric content of inert materials from earthquake demolition waste is about 96%. Such inert material is classified as having an excellent subgrade rating and can be reused as subbase and base soils. The abrasion level of the coarse portions of inert materials from the three sites meets the required level of coarse aggregate according to Standard Taiwan Code CNS-490. On the other hand, the maximum dry unit weights of fines of inert materials from the three sites are greater than 14.7 kN/m3, and their shear strengths are higher than that of the same classification group (SW–SM) of natural soils, so they can be reused as construction soils.