Concrete additive capable of solidifying chlorions efficiently for long time as well as application

Abstract

The invention discloses a concrete additive capable of solidifying chlorions efficiently for a long time as well as a preparation method. A silicon aluminum phase component is added in the concrete additive capable of solidifying chlorions efficiently for a long time and accounts for 20 to 46.75 percent of the total mass of the concrete additive capable of solidifying chlorions efficiently for a long time; the silicon aluminum phase component is bentonite and / or kaolin which is calcined at 400 to 800 DEG C, the particle diameter is 80-um square hole sieve residue less than or equal to 10 percent and the mass percentage of Al2O3 is more than or equal to 35 percent; furthermore, the silicon aluminum phase component can generate Friedel salt (calcium chloraluminate hydrate) with the purity being more than 90 percent under the concrete alkaline environment. According to the concrete additive, the chlorions in the concrete can be solidified efficiently and stabilized for a long time, and the transmission speed of the chlorions in the concrete is effectively reduced. In conclusion, the technology has the technical advantages of low mixing amount (1 to 5 percent by mass of substituted gelmaterial), high chlorion solidification efficiency and long-term stable solidification effect.

Description

technical field [0001] The invention belongs to the technical field of building materials, in particular to a concrete admixture for long-term and high-efficiency curing of chloride ions and its application. Background technique [0002] Reinforced concrete is the main building material for infrastructure construction, accounting for more than 90% of the consumption. At present, the 120-year design service life of the Hong Kong-Zhuhai-Macao Bridge has been proposed, and more and more bridge projects have begun to demonstrate the feasibility of long-life reinforced concrete. [0003] As far as the essence of concrete durability improvement technology is concerned, the main technical principles are mainly divided into two aspects, namely, preventing the depassivation and corrosion of the steel surface and delaying the transmission of aggressive ions in the environment in concrete. The steel corrosion resistance technology involved in the former has formed a relatively mature ...

AI Technical Summary

Problems solved by technology

[0012] Nevertheless, the chloride ion curing agent suitable for concrete in the above-mentioned patent application has the following content that needs further explanation: (1) nitrite type calcium hydroaluminate is not a conventional chemical reagent that can be purchased, and the patent application CN200610145572 does not introduce specific The preparation method, and the chemical thermodynamic calculation or experimental verification of the formation of Friedel salt from nitrite-type calcium hydroaluminate has not been widely carried out, so the actual operability is questionable; (2) Calcium nitrite, slag, fly ash, silica fume The curing chloride ion admixture that is the component is relatively high (25% to 35%), but the curing efficiency of the unit mass admixture to the chloride ion in the concrete is limited, and silica fume has been verified as an effective way to reduce the chloride ion curing ability of the concrete Components (ARYA C, BUENFELD N R, NEWMAN J B.Factors influencing chloride binding inconcrete[J].Cem Concr Res,1990, 20(2):291–300.), so there are improvements in the patent application CN200810030796

(3) Patent application CN201410465488 uses centrifugal separation and spray drying process to prepare layered compound concrete chloride ion curing agent, which requires professional equipment and leads to high production costs; in addition, the layered compound without surface charge modification is only cured by physical adsorption Chloride ions in concrete, there is a risk of secondary precipitation of solidified chloride ions leading to corrosion of steel bars

(4) The magnesium salt used in the patent application CN201610351771 is easy to form magnesium hydroxide crystals in an alkaline environment to generate expansion stress and cause damage and destruction inside the concrete

(5) The use of activated carbon will deteriorate the microstructure of concrete, which will not be conducive to the improvement of concrete strength and anti-permeability; in addition, mesoporous molecular sieves and nano-SiO 2 The use of it will obviously lead to the reduction of concrete fluidity and poor workability, so the feasibility of the patent application CN201611068715 has yet to be verified

[0013] In summary, the above-mentioned literatures all report the chloride ion curing agent, preparation method and application technology for concrete, but the effect of chloride ion curing is not long enough.

Images