The impact of unstable quality of lightweight gypsum mortar: Among commonly used lightweight gypsum mortars, the strength of lightweight gypsum mortar fluctuates greatly and the homogeneity is poor. Analysis of the reasons that easily cause uneven masonry strength:
(1) Inaccurate measurement is the main factor affecting the strength of lightweight gypsum mortar. Due to changes in sand moisture content and loss during transportation, the amount of sand used in lightweight gypsum mortar is lower than the specified amount.
(2) The amount of plasticizing material in cement-mixed lightweight gypsum mortar is very sensitive to the strength of lightweight gypsum mortar. If the plasticizing material exceeds twice the specified amount, the strength of lightweight gypsum mortar will decrease by approximately 40%. However, in order to improve the workability of lightweight gypsum mortar during construction, the amount of plasticized material often exceeds the specified amount, thus reducing the strength of lightweight gypsum mortar.
(3) The light gypsum mortar is not stirred evenly, so that the plasticized materials are not spread out and the cement is unevenly distributed, which affects the uniformity and workability of the light gypsum mortar.
(4) Microfoaming agent is added to cement lightweight gypsum mortar. Due to improper management, the microfoaming agent exceeds the specified amount, which seriously reduces the strength of lightweight gypsum mortar.
(5) The production, maintenance methods and strength values of lightweight gypsum mortar test blocks are not standard, which makes the measured strength of lightweight gypsum mortar lack representativeness.
Prevention and control methods:
(1) Strictly control the mix ratio of lightweight gypsum mortar and strictly carry out measurement work.
(2) Plasticizers (lime plaster, electrogypsum and fly ash) are generally wet materials and are difficult to measure and weigh. In order to strictly control the dosage, the plasticized material can be adjusted to a standard consistency, weighed and measured, and then converted into a standard volume, and checked regularly.
(3) Methods such as increasing the amount of microfoaming agent shall not be used to improve the workability of light gypsum mortar.
(4) Improve the mixing method of light gypsum mortar to make it evenly stirred. Generally, use part of the sand, water and all the plasticizing materials to stir evenly until no lumps are seen, and then add the rest of the sand and water. All cement.
(5) Make, maintain and determine the strength of lightweight gypsum mortar test blocks according to standards. </p
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