Properties and hydration products of lightweight and expansive cements - Part I: Physical and mechanical properties

Results from studies on the physical and mechanical properties of lightweig ht and expansive cements cured at 20 and 75 degrees C are presented. Lightw eight additive (cenospheres from thermoelectric power station "Bobov Dol," Bulgaria) and expansive additive ("Bulexa" with hydroxide type of expansion ) were used. The compressive and flexural strength, the gas and water imper meability, and the pore structure of the cement stone of lightweight and ex pansive cements were investigated. The results are compared with correspond ing parameters of cement stone without additives. It was found that the cen ospheres are appropriate lightweight additives. The use of expansive additi ve helps overcome the dry shrinkage of cement stone and strengthens the bon d with the bounding surfaces. (C) 1999 Elsevier Science Ltd. All rights res erved.