Study on Wood Chip Concrete with Used Timber

Abstract

About 20 million cubic meters of used timber are discharged every year from demolished buildings, mainly wooden houses, in Japan. The authors have carried out a study on recycling used timber as wood-chip concrete. The experiment was carried out as follows. First, the wood chips were filled into a steel mold to achieve the desired packing ratio with a compressive stress of 0.5-1.0 MPa. Then, fresh cement paste was injected into the mold to make the specimens. The densities of the wood-chip concrete in this case generally fall into the range of 920 kg/cu m to 1250 kg/cu m. To evaluate the performance of the wood-chip concrete, bending strength, compressive strength, drying weight loss and shrinkage, thermal conductivity, and thermal expansion were tested. Furthermore, two types of artificial lightweight aggregate were added to the wood-chip mold and cement paste simultaneously to reduce the densities of the concrete, and the compression of the wood chips for packing was not needed in the production process. The densities of the wood-chip concretes with the lightweight aggregates were about 780 kg/cu m to 920 kg/cu m. After these tests, it became clear that the wood-chip concrete will be suitable for use as a building material for partition walls, floor joists, floor boards, etc.