A size-controllable nanocomposite early strength agent and its preparation method

Abstract

The invention discloses a size-controllable nanocomposite early-strength agent and a preparation method thereof. The aqueous solution of an early-strength polycarboxylate water-reducer is added to an aqueous solution of cetyltrimethylammonium bromide and stirred evenly to obtain a pre-strength Disperse the mixed solution; the obtained pre-dispersed mixed solution is stirred and water-bathed, add sodium silicate aqueous solution and calcium nitrate aqueous solution, after the sodium silicate aqueous solution and calcium nitrate aqueous solution are added, continue to react for 1 to 2 days, and carry out coprecipitation reaction. During the precipitation reaction process, the pH value of the control system is maintained between 11 and 13; the obtained reaction system is distilled off under reduced pressure to remove the solvent, freeze-dried, washed with water, and freeze-dried again to obtain the product. The average size of the size-controllable nanocomposite early strength agent prepared by the present invention can be controlled below 200nm, and the dispersibility is good. It can be used as a crystal nucleus growth accelerator of cement hydration product C-S-H gel, thereby improving cement Early strength of hardened paste.

Description

A size-controllable nanocomposite early strength agent and preparation method thereof technical field The present invention relates to concrete additive field, be specifically related to a kind of size-controllable nano-composite early strength agent and preparation thereof. preparation method. Background technique [0002] In recent years, the development of nanotechnology has brought technological innovation and industrial transformation to the traditional cement industry. Nanomaterials should Used in cement-based materials, it can significantly improve the hydration rate, strength, durability, pore structure and other series of cement-based materials. performance. The C-S-H gel in the hardened body of cement-based cementitious materials accounts for more than 70%. If auxiliary cementing materials such as mineral powder are added, the The content of gel is higher; almost all of the low-calcium or calcium-poor silica-alumina system gelling materials are gels. Rapid...

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Problems solved by technology

Although the above-mentioned patents have achieved good results on the early performance of C-S-H / PCE nanocomposite early-strength agents for strengthening cement, there are few references to the size control, measurement and stability of C-S-H / PCE nanocomposite early-strength agents, and the synthesis is early. Stronger particles are larger

Foreign scholars, mainly the Plank research group, have done relevant preparation and hydration research on C-S-H / PCE nanocomposite early strength agents (Cement Concrete Res 2017,102:90-98; Constr Build Mater2018,169:20-27; Cement Concrete Res 2019,119:44-50.), found that the C-S-H / PCE content of 2wt.% can significantly improve the early strength of cement mortar, but the Plank research group focused on the research of C-S-H / PCE on the mortar strength, and the C-S-H / PCE The synthetic ratio research is too single

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