Research On The Preparation And Properties Of Spray Machine Gypsum Plaster

Spray machine gypsum plaster not only caters green, environmentally friendly building themes today, but also changes the traditional cement-based cementitious material habits. It overcomes the traditional plastering material shrinkage of large, poor adhesion due to cracking, empty quality defects such as a drum, and effectively achieves savings the total project cost and labor costs as well as speeding up the construction progress of the project. That Spray machine gypsum plaster replaces lime mortar and cement mortar plastering architectural wall decoration is a trend. The study of the influence factors of its property has important theoretical and practical value.Our study is to select the degradation of the polyamide by calcium from the retarder A, proteins retarder B manufactured by South Korea, protein alkaline retarder C produced by domestic plants and study the consistency of water gypsum building standards affect the amount, setting time, flexural strength, compressive strength and other indicators, combining with over-saturation analysis, SEM morphology analysis, mercury porosimetry pore structure analysis, the rate of hydration, heat of hydration and other mechanism of its role for different viscosity grades of slow-dissolving type instant water retaining agent HPMC building gypsum standard consistency water, water retention rate, flexural strength, compressive strength, tensile bond strength properties of. Eventualy,we use the least type of raw materials to produce good performance spray machine gypsum plaster, and mainly to study the water gypsum ratio, the influence of retarder admixture, HPMC content, slurry stirring rate, paste sand ratio on the machine spray plastering gypsum rheological properties.The results are as follows:(1) Three sequential building gypsum retarder standard consistency water impact from high to low is: B> C> A; three kinds of retarder retarding effect is in the order of A> C> B; three kinds of retarder on building gypsum strength extent of the damage is in the order of B> C> a. Low dosage of 0.02% to 0.03% A retarder can meet the setting time requirement but also to maximize the reduction of building plaster strength loss.(2) Slow-dissolving type HPMC large degree increases the building plaster standard consistency water, the larger type instant HPMC degree of upgrading the building plaster tensile bond strength, and on the flexural and compressive strength of gypsum building damage less, but the effect is not obvious water retention, which 100000Pa?s slow-dissolving type HPMC better overall performance, it is recommended dosage is 0.15% to 0.2%.(3) Spray machine gypsum plaster will control the setting time of about 1h, consistency control in the 90mm~95mm best effect. With slurry yield stress, plastic viscosity and thixotropy characterization of the rheological properties of the slurry, various factors affect the rheological properties of the spray machine plastering gypsum order water paste than> HPMC content> cream-sand ratio> paste stirring rate > A retarder dosage.(4) Retarder mechanism of action studies have shown that reducing the retarder gypsum slurry over saturation, lowering saturation bring slows the rate of hydration of gypsum, making crystallization point of contact less, crystals have sufficient time and space for growth, and then bring the roughening, the deterioration of the crystal structure of the pore structure, resulting in decrease of the strength of the gypsum.