3results about How to "Prolong initial setting time" patented technology

The invention discloses a difunctional gypsum admixture as well as a preparation method and application thereof, and belongs to the technical field of building material admixtures. According to the invention, vegetable tannin is coated on the surfaces of metal oxide nanoparticles, and another metal ion is coordinated on a tannic acid coating layer to assemble core-shell structure nanoparticles, so that the difunctional gypsum admixture is obtained. The difunctional gypsum admixture provided by the invention can delay the gypsum coagulation time and increase the plasticity time of gypsum slurry, after the admixture accounting for 10-50% of the mass of gypsum is introduced, the initial setting time of the gypsum is prolonged to 20-70 min, meanwhile, the assembly of the core-shell structure gives full play to the synergistic effect of the two high Z elements, efficient shielding of the gypsum to X rays is realized, and the strength of the gypsum is improved. Meanwhile, the problem that metal oxide nanoparticles are difficult to uniformly and stably load on gypsum crystals is solved.

The application relates to the technical field of building plugging materials, and particularly provides a long-operable-time plugging material, which is prepared from the following raw materials in terms of total weight: 0.02-3% of a retarder, 0.005-2% of a calcium salt, 0.001-1% of a cellulose ether and cement supplementing to 100%. By optimizing the types of the retarder, the calcium salt and the cellulose ether and by stipulating the relative amounts of the retarder, the calcium salt and the cellulose ether, the quick-setting type plugging material has a relatively long retarding time, and the anti-bending performance, the anti-permeation performance, the bonding performance, the heat resistance and the freeze-thaw cycle resistance of the material after solidification are effectively improved.

This application relates to an admixture for riprap concrete engineering, comprising at least the following components: a starch-dextrin retarder, an activator, a polycarboxylate thixotropic agent, and a water-reducing agent. The admixture is used to modify the workability and hardening properties of high self-compacting concrete. The mass percentages of each component are as follows: starch-dextrin retarder: 1.6%-3.5%; activator: 5.2%-21.3%; polycarboxylate thixotropic agent: 0.25%-0.90%; water-reducing agent: 75.2%-90.5%. Adding this admixture to high self-compacting concrete used in riprap concrete engineering can improve the workability of high self-compacting concrete, such as fluidity, thixotropy, and a longer initial setting time, while also providing good volume stability, good impermeability and frost resistance, and lower cement content, resulting in significant economic benefits.