Influence of methyl-sodium silicate on strength and water resistance of recycled gypsum plaster
Methyl-sodium silicate is commonly used as a waterproofing agent for gypsum,which has a signifi-cant impact on the performance of both construction gypsum and recycled construction gypsum.The water-to-plaster ratio,setting time,strength,and water absorption of the two types of gypsum were measured and com-pared.The changes in the microstructure of recycled construction gypsum were observed.It was found that:(1)the 2-hour flexural strength,compressive strength,dry flexural strength,dry compressive strength,and water ab-sorption of construction gypsum and recycled construction gypsum were 2.5,4.4,5.0,9.5,31.7％and 1.0,1.9,2.3,4.6,62.0％,respectively.Compared with construction gypsum,the strength of recycled construction gypsum decreased by 50％～60％,and the water absorption increased by 95.6％.(2)After adding sodium methylsilicate,the 2-hour flexural and compressive strength,absolute dry flexural and compressive strength,and water absorption of the building gypsum and recycled building gypsum are 2.1,4.0,3.6,7.9,25.7％and 0.7,1.2,1.4,2.6,54.5％,respectively.Compared with building gypsum,the strength reduction of recycled building gypsum is 60.0％～70.0％,and the water absorption increase is 112.1％.By observing the micro-structure,it is found that methyl-sodium silicate can deteriorate the interlocking between the crystals in the hardened body of recycled building gypsum,resulting in a decrease in strength,an increase in water absorp-tion,and a deterioration in waterproofing effect.
recycled gypsum plastermethyl-sodium silicatewater to gypsum ratiostrengthwater resistance
万方数据
维普
