Brick discs with sewage sludge ash: Production data, water absorption, porosity and density measurements

Loss of mass from firing (mfired -m105) was calculated for all brick discs. Firing shrinkage was measured for all brick discs as the shrinkage in diameter. Three measurements of the diameter of each disc were made with a digital calliper. Open porosity, water absorption, and dry density were determined on 3 discs for each test series. The discs were placed in a sealed desiccator under a vacuum for 3 h. After 3 h, the discs were submerged in distilled water, under a vacuum for 1 h, whereafter air was led into the chamber and the discs remained in water at atmospheric pressure for 24 h. The saturated discs were weighed first underwater (msw), then dabbed with a cloth and weighed immediately after above water (mssd). The following properties were calculated: Volume, volume of open pores, apparent density, solid density, porosity, water-solids ratio in vacuum water-saturated surface dry conditions.