Addition of metakaoline to portland cement, influence on hydration and properties of cement-bonded wood composites

摘要

Materials and methods The hydration times and hydration temperatures at 20 ℃ are determined according to Sandermann and Kohler (1964). The equipment used to measure hydration times at 83 ℃ has been described somewhere else (Simatupang et al. 1995). Circular cement-bonded particleboards specimens with a diameter of five cm and target thickness of 12 mm were made from larch or poplar wood particles. Each specimen was made from 6.3 g (oven dry) wood particles. 18.9 g binder and an effective water/binder ratio of 0.40 (Simatupang 1973). The required aluminum sulfate was dissolved in water. Metakaoline was obtained by calcination of kaolinite (Riedel de Haen, Germany) at 750 ℃ for six h. The material was cooled in a desiccator and stored in air-tight containers before use. Portland cement was a PZ 45F. The properties have been published in former literature, see Simatupang and Neubauer 1993.