Substituting masonry concrete units with waterproofing gypsumn anel [sic] gypsum panel

Abstract

Cement is commonly recognized as the most costly binding material used in the construction industry. The possibility of using waterproofing gypsum as a construction material is to be taken into investigation. A comparative study for varying waterproofing materials and their effect on the gypsum’s properties is studied in this paper. That is, when gypsum is mixed with silica fume, silicone oil, and finally with metakaolin. Five mixed of gypsum with water-total powder ratio 0.4 and superplasticizer 2% were made, using silicone oil 0.5%, 0.3% and 0.8% of total powder (gypsum and white cement) ,silica fume 5 % and finally metakaolin 5 % .Then, one mix of gypsum with silicone oil using sicament instead of superplasticizer .These mixed were cast in cube 5cm x 5cm x 5cm and studied the ratio of dry cube -wet cube for 7,14,21, 28 days.The superplasticizer affected the silicone oil negatively and the mix was not successful, so the sicament was replaced and was given good mix and result. The W/(G+C) ratio cannot be less than 0.4 and the presence of superplasticizer or sicament were recommended, since the mix of gypsum dry rapidly, and the mix failed as happened with the trial mixes. The waterproofing materials had high effect on gypsum, which has led to the increase of softening coefficient (compressive strength of dry cube /compressive strength of wet cube) to attain in some mixes 100 %. Moreover, the best mix is used in the gypsum panel mix with extruded polystyrene and glass fiber, then the compressive strength was compared with the masonry units to be replaced.