Corrosion-resistant durable concrete proportioning method

Abstract

The invention discloses a proportioning method of corrosion-resistant durable concrete, which comprises the following components in parts by weight: 100-150 parts of cement, 30-50 parts of pulverized coal balls, 40-60 parts of superfine slag powder, 10-20 parts of silica fume, 200-300 parts of coarse aggregate, 150-250 parts of fine aggregate, 1-3 parts of a water reducing agent, 0.1-0.3 part of an air entraining agent and 40-60 parts of water, the cement is sulfate-resistant portland cement, the pulverized coal balls are spherical particles prepared from fly ash, and the fine aggregate is spherical particles prepared from fly ash. Active components in the fly ash and a cement hydration product calcium hydroxide are subjected to a secondary hydration reaction to generate more gelling substances, and the cement, the fly ash and the superfine slag powder jointly construct a compact structure, so that invasion of corrosive ions such as chloride ions and sulfate ions is effectively blocked, and the corrosion resistance of the cement is improved. The corrosion risk of concrete in marine environments, chemical pollution areas and other high-corrosion environments is greatly reduced, the water-binder ratio is reduced through the water reducing agent, pores formed by free water in the concrete are reduced, the impermeability of the concrete is remarkably improved, and therefore the durability of the concrete is improved, and the service life of the concrete is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete, and in particular relates to a method for mixing proportions of corrosion-resistant and durable concrete. Background Art

[0002] Concrete is one of the most important civil engineering materials in contemporary times. It is an artificial stone made by mixing cementitious materials, granular aggregates, water, and admixtures and additives added in a certain proportion when necessary, and then evenly mixing, compacting, and curing to harden.

[0003] Currently, when concrete is used for construction in coastal areas or saline areas, chloride ions in the soil or seawater will corrode the concrete, penetrate into the surface of the steel bars, reduce the pH value of the steel bar surface, destroy the passivation film on the steel bar surface, and accelerate the corrosion of the steel bars, which not only affects the bonding performance between concrete and steel bars, but also accelerates the appearance of concrete cracks under load, thereby reducing the durability of the concrete and reducing the effective bearing area of ​​reinforced concrete, thus seriously affecting the service life and safety of the building. Summary of the invention

[0004] The object of the present invention is to provide a method for mixing proportions of corrosion-resistant and durable concrete to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a corrosion-resistant and durable concrete mix ratio, which comprises, by weight, 100-150 parts of cement, 30-50 parts of pulverized coal balls, 40-60 parts of slag powder, 10-20 parts of silica fume, 200-300 parts of coarse aggregate, 150-250 parts of fine aggregate, 1-3 parts of water reducer, 0.1-0.3 parts of air entraining agent and 40-60 parts of water.

[0006] Preferably, by weight, it includes 130 parts of cement, 35 parts of pulverized coal balls, 55 parts of slag powder, 18 parts of silica fume, 275 parts of coarse aggregate, 230 parts of fine aggregate, 2.5 parts of water reducer, 0.26 parts of air entraining agent, and 55 parts of water.

[0007] Preferably, the cement is sulfate-resistant Portland cement.

[0008] Preferably, the pulverized coal balls are spherical particles made of fly ash.

[0009] Preferably, the coarse aggregate is crushed granite, basalt or limestone, and the fine aggregate is river sand.

[0010] Preferably, the water reducer is a high-performance polycarboxylic acid water reducer, and the air entraining agent is a rosin resin air entraining agent.

[0011] A method for mixing proportions of corrosion-resistant and durable concrete comprises the following steps:

[0012] S1. Put cement, pulverized coal balls, slag powder, silica fume, coarse aggregate and fine aggregate into a mixer in proportion, and dry mix for 3-5 minutes to make the solid materials fully mixed;

[0013] S2, dissolving the water reducing agent and the air entraining agent in water to form an admixture solution;

[0014] S3. While the mixer is stirring continuously, slowly add the admixture solution into the dry mix and continue stirring for 5-9 minutes until the concrete is mixed evenly to form a corrosion-resistant and durable concrete.

[0015] Compared with the prior art, the invention has the following beneficial effects: through the synergistic effect between cement, fly ash, slag powder and silica fume, the active ingredients in fly ash react with calcium hydroxide, a cement hydration product, to generate more cementitious substances to fill the internal pores of concrete; the highly active glass of slag powder further strengthens the gelling effect in an alkaline environment, thereby enhancing the resistance of concrete to chemical erosion; silica fume, with its extremely small particle size, can fill into even smaller pores, and together with cement, fly ash and slag powder, build a dense structure, effectively blocking chloride ions and sulfate ions. The invasion of corrosive ions such as ions greatly reduces the risk of concrete being corroded in highly corrosive environments such as marine environments and chemical pollution areas. The water-cement ratio is reduced by the water reducer, and the pores formed by free water inside the concrete are reduced. The tiny bubbles introduced by the air entraining agent are evenly distributed in the concrete. These bubbles cut off the connecting channels between the pores to a certain extent, which significantly improves the impermeability of the concrete. The enhancement of impermeability can effectively prevent moisture and corrosive substances dissolved therein from entering the interior of the concrete, thereby improving the durability of the concrete and greatly extending the service life of the concrete. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] The invention provides a corrosion-resistant and durable concrete mix ratio, which comprises, by weight, 100-150 parts of cement, 30-50 parts of pulverized coal balls, 40-60 parts of slag powder, 10-20 parts of silica fume, 200-300 parts of coarse aggregate, 150-250 parts of fine aggregate, 1-3 parts of water reducer, 0.1-0.3 parts of air entraining agent and 40-60 parts of water.

[0018] By weight, it includes 130 parts of cement, 35 parts of pulverized coal balls, 55 parts of slag powder, 18 parts of silica fume, 275 parts of coarse aggregate, 230 parts of fine aggregate, 2.5 parts of water reducer, 0.26 parts of air entraining agent, and 55 parts of water.

[0019] The cement is sulfate-resistant Portland cement.

[0020] The pulverized coal balls are spherical particles made of fly ash. The pulverized coal balls can improve the working performance of concrete, increase its fluidity, reduce water consumption, and thus reduce the water-binder ratio, and enhance the impermeability and corrosion resistance.

[0021] The coarse aggregate is crushed granite, basalt or limestone, and is made of hard, well-graded crushed stone with a particle size range of 5-25 mm. The good gradation of the coarse aggregate can ensure that the concrete has sufficient skeleton strength and reduce porosity. The fine aggregate is river sand, and the river sand uses medium sand with a fineness modulus of 2.6-3.0 mm. The particle size of the medium sand is moderate, which can better fill the gaps between the coarse aggregates and form a dense structure together with the cement slurry.

[0022] The water reducer is a high-performance polycarboxylate water reducer, which can significantly reduce the water-cement ratio. The low water-cement ratio helps to reduce the pores and microcracks inside the concrete, improve the density and strength of the concrete, and thus enhance the corrosion resistance. The air entraining agent is a rosin resin air entraining agent, which can introduce an appropriate amount of uniformly distributed tiny bubbles into the concrete. When the concrete is subjected to freeze-thaw cycles or other external forces, the bubbles can play a buffering role, reduce the accumulation of internal stress, and improve the freeze-thaw resistance of the concrete.

[0023] A method for mixing proportions of corrosion-resistant and durable concrete comprises the following steps:

[0024] S1. Put cement, pulverized coal balls, slag powder, silica fume, coarse aggregate and fine aggregate into a mixer in proportion, and dry mix for 3-5 minutes to make the solid materials fully mixed;

[0025] S2, dissolving the water reducing agent and the air entraining agent in water to form an admixture solution;

[0026] S3. While the mixer is stirring continuously, slowly add the admixture solution into the dry mix and continue stirring for 5-9 minutes until the concrete is mixed evenly to form a corrosion-resistant and durable concrete.

[0027] By comparing the performance of concrete prepared by the mixing method of the present invention with that of traditional concrete in different corrosion environments, the effectiveness of the mixing method of the present invention in improving the corrosion resistance and durability of concrete is verified;

[0028] The concrete prepared by the mixing method of the present invention and the traditional concrete were mixed evenly according to the standard mixing process, and then made into cubic specimens with a size of 100 mm×100 mm×100 mm. The number of specimens was 10, which were used for testing in different corrosion environments and cured for 28 days under standard curing conditions (temperature 20±2°C, relative humidity above 95%).

[0029] Experiment 1:

[0030] The specimens were immersed in a solution containing 3.5% sodium chloride and 0.5% sodium sulfate, with the solution temperature maintained at 25°C to simulate the marine environment;

[0031] The comparative test results of the concrete prepared by the mix ratio method of the present invention and the traditional concrete are shown in Table 1 below:

[0032] Table 1 Comparative experimental results of concrete in Experiment 1 and traditional concrete

[0033] Number of days Day 90 Day 180 Day 360 Concrete of the present invention 3％ 7％ 10％ Traditional concrete 8％ 15％ 22％

[0034] Before immersion and after 90 days, 180 days, and 360 days of immersion, the compressive strength of the cubic specimens was tested, and the compressive strength loss rate was calculated, where compressive strength loss rate = (compressive strength before immersion - compressive strength after immersion) / compressive strength before immersion × 100%;

[0035] Experimental results:

[0036] The compressive strength loss rates of the concrete of the present invention after immersion for 90 days, 180 days and 360 days are 3%, 7% and 10% respectively, while the compressive strength loss rates of the conventional concrete at the same time points are 8%, 15% and 22% respectively;

[0037] After 360 days, the surface of the concrete specimen of the present invention had a slight discoloration phenomenon, and a light white salt frost appeared, and some tiny cracks were generated on the surface under the action of pressure, while the surface color of the traditional concrete specimen changed significantly, and a large area of ​​white salt frost appeared, and a mesh structure crack with a width of millimeters was generated under the action of pressure.

[0038] Experiment 2:

[0039] The specimens were placed in a fog chamber containing 0.5% sulfur dioxide and 0.5% sodium sulfate, with a temperature of 30°C and a relative humidity of 70%, simulating a chemical pollution environment;

[0040] The comparative test results of the concrete prepared by the mixing method of the present invention and the traditional concrete under chemical pollution environment are shown in Table 2 below:

[0041] Table 2 Comparison test results of concrete in Experiment 2 and traditional concrete

[0042] Number of days Day 60 Day 120 Day 240 Concrete of the present invention 0.5％ 1.2％ 2.0％ Traditional concrete 1.5％ 3.0％ 5.0％

[0043] Before placement and after 60 days, 120 days, and 240 days of placement, weigh the specimens and calculate the mass loss rate, mass loss rate = (mass before placement - mass after placement) / mass before placement × 100%;

[0044] Experimental results:

[0045] The mass loss rates of the concrete of the present invention after being placed for 60 days, 120 days and 240 days are 0.5%, 1.2% and 2.0% respectively, while the mass loss rates of the conventional concrete at the same time points are 1.5%, 3.0% and 5.0% respectively;

[0046] After 240 days, the surface of the concrete specimens of the present invention showed only slight signs of corrosion, with an average corrosion depth of 2 mm, while the surface of the conventional concrete specimens was severely corroded, with a large amount of peeling, and an average corrosion depth of 8 mm;

[0047] It can be seen from Tables 1-2 that through the above comparative experiments, it can be seen that in the simulated marine environment and the simulated chemical pollution environment, the concrete prepared by the proportioning method of the present invention is significantly superior to the traditional concrete in terms of compressive strength loss rate, resistance to chloride ion penetration, mass loss rate and corrosion resistance depth, thereby proving that the corrosion-resistant and durable concrete proportioning method of the present invention can effectively improve the performance of concrete in harsh corrosion environments.

[0048] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A corrosion-resistant and durable concrete mix, characterized in that: Calculated by weight, it includes 100-150 parts of cement, 30-50 parts of pulverized coal balls, 40-60 parts of slag powder, 10-20 parts of silica fume, 200-300 parts of coarse aggregate, 150-250 parts of fine aggregate, 1-3 parts of water reducer, 0.1-0.3 parts of air entraining agent and 40-60 parts of water.

2. The corrosion-resistant and durable concrete mix according to claim 1, characterized in that: By weight, it includes 130 parts of cement, 35 parts of pulverized coal balls, 55 parts of slag powder, 18 parts of silica fume, 275 parts of coarse aggregate, 230 parts of fine aggregate, 2.5 parts of water reducer, 0.26 parts of air entraining agent, and 55 parts of water.

3. The corrosion-resistant and durable concrete mix according to claim 1, characterized in that: The cement is sulfate-resistant Portland cement.

4. The corrosion-resistant and durable concrete mix according to claim 1, characterized in that: The pulverized coal balls are spherical particles made of fly ash.

5. The corrosion-resistant and durable concrete mix according to claim 1, characterized in that: The coarse aggregate is crushed granite, basalt or limestone, and the fine aggregate is river sand.

6. The corrosion-resistant and durable concrete mix according to claim 1, characterized in that: The water reducing agent is a high-performance polycarboxylic acid water reducing agent, and the air entraining agent is a rosin resin air entraining agent.

7. A method for mixing proportions of corrosion-resistant and durable concrete according to any one of claims 1 to 6, characterized in that: The specific steps include: S1. Put cement, pulverized coal balls, slag powder, silica fume, coarse aggregate and fine aggregate into a mixer in proportion, and dry mix for 3-5 minutes to make the solid materials fully mixed; S2, dissolving the water reducing agent and the air entraining agent in water to form an admixture solution; S3. While the mixer is continuously stirring, slowly add the admixture solution into the dry mix and continue stirring for 5-9 minutes until the concrete is mixed evenly to form a corrosion-resistant and durable concrete.