Concrete mineral admixture capable of improving chloride ion penetration resistance and concrete

Abstract

The invention provides a concrete mineral admixture capable of improving chloride ion penetration resistance. The concrete mineral admixture is characterized by comprising the following components inpercentage by weight: 40-70% of calcined kaolin tailings, 20-50% of limestone powder, 0-10% of gypsum, 0-5% of slaked lime, 0-0.02% of a water-retaining agent and 0-0.5% of an early strength agent. According to the mineral admixture, a large amount of accumulated kaolin tailings and widely existing limestone are used as raw materials and matched with other additives, and the mineral admixture is simple in production process, low in cost, energy-saving and environment-friendly. The mineral admixture can effectively improve the capability of resisting chloride ion penetration of concrete in theearly stage.

Description

technical field

[0001] The invention belongs to the field of building materials, in particular to a concrete mineral admixture and concrete which can improve the anti-chloride ion penetration ability. Background technique

[0002] The introduction of steel bars in reinforced concrete improves the mechanical properties of concrete and is widely used in the field of engineering and construction. The steel bar will form a passivation film on the surface of the steel bar under the alkaline condition of the concrete, which makes the steel bar in the reinforced concrete have better corrosion resistance. However, the presence of chloride ions can destroy the structure of the passivation film of the steel bar, making the steel bar prone to electrochemical corrosion, resulting in a decrease in strength and failure of the steel bar. At the same time, when the steel bar corrodes, it will expand, which will eventually lead to component failure and cause great economic losses.

[0003] ...

Examples

Embodiment 1

[0026] This embodiment provides a kind of concrete mineral admixture that improves anti-chloride ion penetration ability, and described concrete mineral admixture comprises calcined kaolin tailings 63%, limestone powder 32%, gypsum 2.69%, slaked lime 2%, according to weight percentage, Modified starch 0.01% and Glauber's salt 0.3%.

[0027] After uniform mixing in a mixer, the concrete mineral admixture L1 is obtained.

[0028] In this example, the preparation method of the calcined kaolin tailings is: calcining the kaolin tailings completely at 750-850°C, after cooling, adding a grinding aid accounting for 0.05-0.2% of the tailings mass fraction, and grinding them into calcined kaolin Tailings powder, specific surface area greater than 500m 2 / kg. When grinding, the grinding aid and absolute ethanol are diluted into a solution according to the volume ratio of 1:3-1:1, and the grinding time is 20-40min. The grinding aid is alkanolamine series. In the present embodiment, de...

Embodiment 2

[0030] This embodiment is roughly the same as Embodiment 1, except that the concrete mineral admixture includes 50% of calcined kaolin tailings, 45% of limestone powder, 4.38% of gypsum, 0.5% of slaked lime, and 0.02% of modified starch according to the percentage by weight. % and thenardite 0.1%.

[0031] The concrete mineral admixture L2 is obtained after being uniformly mixed in a mixer.

Embodiment 3

[0033] This embodiment is roughly the same as Embodiment 1, except that the concrete mineral admixture includes 65% of calcined kaolin tailings, 25% of limestone powder, 4.49% of gypsum, 5% of slaked lime, and 0.01% of modified starch according to the percentage by weight. % and thenardite 0.5%.

[0034] The concrete mineral admixture L3 is obtained after being uniformly mixed in a mixer.

[0035] The raw materials used to configure concrete are cement, the above-mentioned mineral admixtures L1 to L3, and fly ash and mineral powder used as comparison. The fine aggregate is river sand with a modulus of 2.5, the coarse aggregate is 5-25mm continuous graded gravel, and the water is tap water. The specific mixing ratio is listed in Table 1. The water reducer used is a polycarboxylate high-efficiency water reducer with a solid content of 20%.

technical field

[0001] The invention belongs to the field of building materials, in particular to a concrete mineral admixture and concrete which can improve the anti-chloride ion penetration ability. Background technique

[0002] The introduction of steel bars in reinforced concrete improves the mechanical properties of concrete and is widely used in the field of engineering and construction. The steel bar will form a passivation film on the surface of the steel bar under the alkaline condition of the concrete, which makes the steel bar in the reinforced concrete have better corrosion resistance. However, the presence of chloride ions can destroy the structure of the passivation film of the steel bar, making the steel bar prone to electrochemical corrosion, resulting in a decrease in strength and failure of the steel bar. At the same time, when the steel bar corrodes, it will expand, which will eventually lead to component failure and cause great economic losses.

[0003] ...

Examples

Embodiment 1

[0026] This embodiment provides a kind of concrete mineral admixture that improves anti-chloride ion penetration ability, and described concrete mineral admixture comprises calcined kaolin tailings 63%, limestone powder 32%, gypsum 2.69%, slaked lime 2%, according to weight percentage, Modified starch 0.01% and Glauber's salt 0.3%.

[0027] After uniform mixing in a mixer, the concrete mineral admixture L1 is obtained.

[0028] In this example, the preparation method of the calcined kaolin tailings is: calcining the kaolin tailings completely at 750-850°C, after cooling, adding a grinding aid accounting for 0.05-0.2% of the tailings mass fraction, and grinding them into calcined kaolin Tailings powder, specific surface area greater than 500m 2 / kg. When grinding, the grinding aid and absolute ethanol are diluted into a solution according to the volume ratio of 1:3-1:1, and the grinding time is 20-40min. The grinding aid is alkanolamine series. In the present embodiment, de...

Embodiment 2

[0030] This embodiment is roughly the same as Embodiment 1, except that the concrete mineral admixture includes 50% of calcined kaolin tailings, 45% of limestone powder, 4.38% of gypsum, 0.5% of slaked lime, and 0.02% of modified starch according to the percentage by weight. % and thenardite 0.1%.

[0031] The concrete mineral admixture L2 is obtained after being uniformly mixed in a mixer.

Embodiment 3

[0033] This embodiment is roughly the same as Embodiment 1, except that the concrete mineral admixture includes 65% of calcined kaolin tailings, 25% of limestone powder, 4.49% of gypsum, 5% of slaked lime, and 0.01% of modified starch according to the percentage by weight. % and thenardite 0.5%.

[0034] The concrete mineral admixture L3 is obtained after being uniformly mixed in a mixer.

[0035] The raw materials used to configure concrete are cement, the above-mentioned mineral admixtures L1 to L3, and fly ash and mineral powder used as comparison. The fine aggregate is river sand with a modulus of 2.5, the coarse aggregate is 5-25mm continuous graded gravel, and the water is tap water. The specific mixing ratio is listed in Table 1. The water reducer used is a polycarboxylate high-efficiency water reducer with a solid content of 20%.

Images