An alkali-free high-strength concrete accelerator

Abstract

The invention discloses an alkali-free high-strength concrete flash setting admixture.The flash setting admixture comprises, by weight, 11%-20% of Portland cement, 13%-19% of aluminum oxygen chamotte, 5%-11% of naphthalenesulfonic acid-formaldehyde condensate, 6%-12% of bentonite, 15%-21% of coal ash, 5%-11% of gypsum, 1%-7% of zinc sulfate, 1%-2% of sodium aluminate, 2%-8% of sodium carbonate, 4%-10% of hydroxypropyl methyl cellulose and 6%-12% of silica fume.The alkali-free high-strength concrete flash setting admixture has the advantages that the flash setting admixture is short in setting time and capable of promoting concrete to set primarily within 3 minutes and set finally within 8 minutes and can have strength after 0.8 hour, later strength develops slowly, and both early strength and later strength are high; the concrete is excellent in homogeneity, high in anti-penetrability performance, little in dust and small in rebound quantity; the alkali-free chloride-free concrete has no corrosive effect on rebars and is highly adaptable to cement.

Description

technical field [0001] The invention relates to an alkali-free high-strength concrete accelerator. Background technique [0002] Concrete quick-setting agent, also known as coagulant, is a chemical admixture that can promote the rapid setting of cement or concrete. It is widely used in bolting and shotcreting support in mine shafts, tunnels and other projects, as well as plugging and emergency repair projects. Accelerator as a chemical product, its production and use can be traced back to the 1930s. The birth and use of accelerators make shotcrete construction possible, and play an important role in the establishment of shaft shotcrete support technology. The performance indicators to measure the quality of the accelerator mainly include the physical and chemical properties and state of the accelerator itself, the accelerator effect, early strength, later strength, volume stability, durability and other performance, as well as dispersion uniformity, dust and spraying. Inje...

AI Technical Summary

Problems solved by technology

(2) The quick-setting agent used in our country has a high alkalinity. On the one hand, the high alkalinity will cause great corrosion to the construction personnel, and on the other hand, it will reduce the strength of the concrete

(3) Accelerators are not effective in reducing dust, reducing rebound rate, and reducing dust

(4) There are deficiencies such as unsatisfactory comprehensive performance to varying degrees

The main manifestations are: the water absorption of the sprayed layer is high, resulting in poor quality of the sprayed layer, large shrinkage rate, poor impermeability of the sprayed layer, poor corrosion resistance, unsatisfactory mixing ratio, unsatisfactory compatibility, and poor adaptability to different cements , high cost etc.