CN107986643A - A kind of admixture prepared with gypsum activation slag and miberal powder and the high performance concrete prepared using admixture - Google Patents

Abstract

The invention discloses a kind of admixture prepared with gypsum activation slag and miberal powder and the high performance concrete prepared using admixture.The admixture is by slag, miberal powder and gypsum with weight ratio（8~10）：（20~22）：（1~3）Mixing composition.The high performance concrete includes following component：300~500 parts of cementitious material；1000~1200 parts of building stones；600~700 parts of sand；100~150 parts of water；3~10 parts of water-reducing agent；Admixture is the 25%~35% of total cementitious material.Activity of the invention by using gypsum activation slag, and the mutual excitation between slag and miberal powder, improve slag and the mixed activity of miberal powder, by using the admixture of the high activity concrete is prepared instead of part of cement, while can ensureing working performance of concrete, it is obviously improved the early strength and later strength of concrete, and the activity index of concrete.

Description

A kind of admixture prepared by using gypsum to excite steel slag and mineral powder and using the admixture to prepare high performance concrete

technical field

The invention belongs to the technical field of building materials, and more specifically relates to an admixture prepared by using gypsum to excite steel slag and mineral powder and high-performance concrete prepared by using the admixture.

Background technique

In recent years, nearly 3 billion cubic meters of concrete has been used in infrastructure construction and national key project construction in my country every year, which has played an important role in national economic growth and social progress. But at the same time, the rapid development of the cement concrete industry consumes a lot of resources and energy, and emits a lot of greenhouse gases, causing serious pollution to the environment. The cement required for the concrete produced in China needs to burn nearly 180 million tons of standard coal, which directly produces nearly 900 million tons of CO ₂ , accounting for about 10% of the world's CO ₂ emissions.

At the same time, my country is an important steel producer. my country's steel output has been ranked first in the world for 14 consecutive years, and it is far ahead of other countries. With the rapid development of the iron and steel industry, its solid waste emissions are also increasing rapidly. In 2010, the national industrial solid waste generation was 2,409.435 million tons, and the iron and steel discharge was 4.982 million tons. If these solid wastes are not effectively utilized and piled up for a long time, they will occupy land, silt up river courses, damage the environment and cause pollution. Steel slag, slag and fly ash are the main industrial wastes of my country's iron and steel industry. Among them, slag and fly ash have been effectively used in cement and concrete industries, and the utilization rate of slag has reached more than 90%. The application of ash in cement concrete is also very common. In contrast, the utilization rate of steel slag has been low due to its low activity and stability problems.

At present, the active activation methods of fly ash, steel slag, slag and other mineral admixtures at home and abroad mainly include physical fine grinding, single doping of activator and calcium addition treatment. However, the activation effect and utilization rate of steel slag still need to be further improved. Therefore, looking for a suitable steel slag and mineral powder active activator can further improve the activity of steel slag and mineral powder admixture, increase the mixing ratio of steel slag while increasing the strength of concrete, and reduce the amount of raw materials used in cement production and cement production. Energy consumption and cement production pollutant emissions, increasing the added value of steel slag and mineral powder, and meeting the development of a green and low-carbon economy have great application value.

Contents of the invention

The object of the present invention is to provide an admixture prepared by using gypsum to excite mineral powder and steel slag. By adopting the excitation effect of gypsum on steel slag, as well as the synergistic and mutual excitation effect of steel slag and mineral powder, the activity of the admixture prepared by steel slag, mineral powder and gypsum is better improved, and part of cement is replaced by this admixture The prepared concrete has better early strength and later strength.

Another object of the present invention is to provide the application of the admixture in the preparation of concrete.

Another object of the present invention is a high performance concrete. The admixture described in the present invention is added to the high-performance concrete to replace part of the cement to prepare concrete; the admixture not only overcomes the reduction of concrete strength caused by single-mixed steel slag, but also enhances the working performance of the concrete , early strength and late strength.

Above-mentioned purpose of the present invention is achieved through the following technical solutions:

An admixture prepared by using gypsum to stimulate steel slag and mineral powder, the admixture is composed of steel slag, mineral powder and gypsum in a weight ratio of (8-10):(20-22):(1-3).

The principle of mutual activation of steel slag and mineral powder: compound finely ground steel slag powder and mineral powder. On the one hand, the specific surface area of the steel slag powder and mineral powder used is larger than that of cement, which can provide better particle gradation and make the concrete more compact. State; on the other hand, mineral powder can reduce the C/S ratio of steel slag-mixed cementitious materials, so that the amount of xonotlite in the hydration product increases, which is manifested as an increase in the strength of cement stone. In addition, the SiO ₂ in mineral powder And MgO, FeO, etc. will generate hydration products with higher strength. In terms of mutual coordination, mineral powder and steel slag are compounded as admixtures. On the one hand, mineral powder can absorb free calcium oxide in steel slag to overcome the problem of poor stability of steel slag. On the other hand, free calcium oxide and its water content in steel slag Calcium hydroxide, the product of calcium hydroxide, can also be used as an activator for the secondary hydration reaction of mineral powder, and the combination of the two has high practical value.

The activation principle of gypsum on steel slag and mineral powder: Although steel slag and ore contain more CaO, the formation of free Ca ⁺ is very little, while gypsum can provide more free Ca ⁺ , and the free Ca ⁺ can be hydrated with SiO ₂ , Fe ₂ O ₃ , Al ₂ O ₃ in steel slag react to generate corresponding hydration products, namely calcium silicate hydrate, calcium ferrite hydrate, calcium aluminate hydrate, etc.; in addition, the gypsum provided SO ₄ - can react with C ₃ A and C ₄ AF in steel slag and mineral powder to form ettringite. Because of the addition of an appropriate proportion of gypsum, the content of calcium silicate hydrate, calcium ferrite hydrate, calcium aluminate hydrate, etc. and ettringite in the mixed admixture increases, thereby improving the activity of the admixture , and then the early strength and late strength of the concrete prepared by using the admixture are improved.

Preferably, the admixture is composed of steel slag, mineral powder and gypsum mixed in a weight ratio of 9:21:2.

Preferably, the steel slag is converter steel slag of Shaoyang Iron and Steel Co., Ltd., with a specific surface area of 500-700m ² /kg; the calcium oxide content of the steel slag is less than 50%. The steel slag is converter steel slag provided by Shaogang Iron and Steel Group Co. _, Ltd. The main components _{of its chemical composition are CaO, SiO 2 ,} Fe ₂ O ₃ Similar in composition, possessing latent gelling activity.

Preferably, the ore powder is S95 granulated blast furnace slag fine powder provided by Shaogang Iron and Steel Group Co., Ltd., with a density of 2.83g/cm3 and a specific surface area of 413m ² /kg. The main components of its chemical composition are CaO, SiO ₂ , and Al ₂ O ₃ . Although the CaO content is relatively high, the free CaO content is not much. And the contents of CaO, SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ and MgO are similar to the chemical composition of cement, and have potential gelling activity.

At the same time, the invention also protects the application of the admixture in the preparation of high-performance concrete.

The present invention also protects the high-performance concrete prepared by using the admixture. The high-performance concrete includes the following components: 300-500 parts of cementitious material; 1000-1200 parts of stone; 600-700 parts of sand; 100-500 parts of water 150 parts; 3-10 parts of water reducing agent; the admixture is 25%-35% of the total gelling material. The total cementitious material consists of cementitious material and admixtures.

Preferably, the admixture comprises 30% of the total gelling material.

Preferably, the water-binder ratio of the high-performance concrete is 0.25-0.28, which is the ratio of water consumption to total gel material consumption.

Preferably, the water-binder ratio of the high-performance concrete is 0.26, which is the ratio of water consumption to total gel material consumption.

Preferably, the high-performance concrete includes the following components: 343 parts of cementitious material; 1090 parts of stone material; 668 parts of sand; 125 parts of water; 9.8 parts of water reducer;

Advantages and beneficial effects of the present invention:

The invention improves the activity of steel slag and mineral powder by using gypsum to stimulate the activity of steel slag and the interaction between steel slag and mineral powder. By using this highly active admixture instead of part of cement to prepare concrete, it can ensure While improving the working performance of concrete, it can obviously improve the early strength and later strength of concrete and the activity index of concrete. The raw material of the invention is cheap and easy to obtain, not only relieves the pressure of high-strength concrete on cement consumption, but also improves the effect of steel slag or mineral powder as admixture, and meets the needs of sustainable development.

Detailed ways

The present invention will be described in further detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto. The following examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above examples, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

The preparation of embodiment 1 admixture

The preparation process of the admixture: After mechanically grinding the converter steel slag of Shaogang, the steel slag powder with a specific surface area of 500-700m ² /kg is obtained; the S95 grade granulated blast furnace slag powder provided by Shaogang Iron and Steel Group Co., Ltd. has a density of 2.83 g/cm ³ , the specific surface area is 413m ² /kg; gypsum purchased on the market; the three are mixed at a mass ratio of 9:21:2 to obtain the admixture, which is recorded as GF. The chemical compositions of steel slag and slag powder are shown in Table 1 and Table 2 below, respectively.

Table 1 Steel slag chemical composition (%)

Table 2 Mineral Powder Chemical Composition (%)

The preparation of embodiment 2 concrete

The GF prepared in Example 1 is used to prepare high-performance concrete, and the cement used for preparing the concrete is P.II42.5R cement produced by Guangzhou Zhujiang Cement Co., Ltd.; the crushed stone is the crushed stone provided by Guangzhou Ande Construction Components Co., Ltd., The place of origin is Zengcheng Yonghe, and the rock type is granite; the water reducer is the polycarboxylate high-performance water reducer HPC-R provided by Guangzhou Ande Construction Components Co., Ltd., and the water reducer is light brown liquid.

The raw materials and dosage used in concrete preparation are shown in Table 3. In the preparation process of the 10 groups of concrete, except for the cementitious material, the dosage of other raw materials and the preparation method are consistent. The admixture in the cementitious material is 30% of the total cementitious material instead of cement, and is mixed with net cement concrete, the same amount of single-mixed steel slag, single-mixed mineral powder, and steel slag and mineral powder at a ratio of 15:15 or 21:9. Concrete comparison prepared with mixed admixtures. For the gypsum stimulator, a blank control and quicklime positive control were used. The working performance and compressive strength of the prepared concrete are shown in Table 4.

Table 3 concrete mix ratio

Table 4 Concrete work performance and compressive strength

According to the analysis of the results in Table 4, from the data of the 2nd to 4th groups, compared with the single mixing of steel slag or slag powder, even if no activator is added, the concrete prepared by the binary compound of steel slag and slag powder has better working performance and compressive strength. Both strength and activity index increased slightly. It can be seen that after the binary compounding of steel slag and mineral powder, the two have better synergy and mutual excitation.

From the data of Group 4 and Groups 8-10, in the case of the same mixing ratio of steel slag and mineral powder, the concrete prepared by adding gypsum is obviously improved in terms of work performance, compressive strength and activity index; among them When the weight ratio of steel slag: slag: gypsum is 9:21:2, the working performance, compressive strength and activity index of concrete are the best, that is, the data of group 9 in Table 4, which has obvious advantages in early strength and later strength. improvement. From the data of the 7th group and the data of the 8th to 10th groups, when the amount of gypsum is too small, that is, when the amount of gypsum is not within the protection scope of the present invention, its activation effect on steel slag is relatively poor, and the early stage of the prepared concrete Intensity and late strength improvement effects are not obvious. It can be seen that gypsum has an exciting effect on the activity of steel slag and mineral powder, and when the amount of the three is only within the proportion range of the present invention, the activity of the admixture is better, and the early strength and later strength of concrete can be obviously improved. .

From the data of Group 1 and Group 5, compared with the concrete prepared with pure cement, when quicklime is used as the activator, the compressive strength and activity index of the concrete are improved, but the improvement effect is not obvious. From the data of Group 5 and Group 8-10, when gypsum is used as the activator, the compressive strength and activity index of the concrete are significantly higher than those prepared with quicklime as the activator. It can be seen that the stimulating effect of gypsum on the activity of steel slag and mineral powder composite admixture is obviously stronger than that of quicklime.

In summary, when gypsum is used as the activator of steel slag and mineral powder, the activity of steel slag and mineral powder is greatly stimulated. Using this admixture to prepare concrete can significantly improve the performance of concrete under the premise of ensuring the performance of concrete. Compressive strength and activity index of concrete.

Claims (10)

1. A kind of 1. admixture prepared with gypsum activation slag and miberal powder, it is characterised in that the admixture by slag, miberal powder and Gypsum is with mass ratio（8~10）：（20~22）：（1~3）Mixing composition.
2. 2. admixture according to claim 1, it is characterised in that the admixture is by slag, miberal powder and gypsum with quality Than 9：21：2 mixing compositions.
3. 3. admixture according to claim 1, it is characterised in that the slag is splendid steel converter slag, and specific surface area is 500~700m²/kg；The content of slag calcium oxide is less than 50%.
4. 4. admixture according to claim 1, it is characterised in that the slag is S95 grades of graining blast-furnace cinder micro-powders, close Spend for 2.83g/cm³, specific surface area 413m²/kg。
5. A kind of 5. application of any admixture of Claims 1 to 4 in high performance concrete is prepared.
6. 6. a kind of high performance concrete, it is characterised in that the high performance concrete includes following component：Cementitious material 300~ 500 parts；1000~1200 parts of building stones；600~700 parts of sand；100~150 parts of water；3~10 parts of water-reducing agent；Claims 1 to 4 is appointed One admixture is the 25%~35% of total cementitious material.
7. 7. high performance concrete according to claim 6, it is characterised in that admixture accounts for the 30% of total cementitious material.
8. 8. high performance concrete according to claim 6, it is characterised in that the water-cement ratio of the high performance concrete is 0.25~0.28.
9. 9. high performance concrete according to claim 8, it is characterised in that the water-cement ratio of the high performance concrete is 0.26。
10. 10. high performance concrete according to claim 6, it is characterised in that the high performance concrete includes such as the following group Point：343 parts of cementitious material；1090 parts of building stones；668 parts of sand；125 parts of water；9.8 parts of water-reducing agent；Admixture is total cementitious material 30%。