CN108863120A - A kind of high-strength sulphoaluminate cement base material and preparation method thereof - Google Patents

Abstract

The present invention relates to a kind of high-strength sulphoaluminate cement base materials and preparation method thereof, are made of following raw material by weight percentage：Sulphoaluminate cement clinker 50 ~ 60%, flyash 25 ~ 35%, gypsum 5 ~ 15%, exciting agent 5 ~ 15%；The exciting agent is the sulphur calcium silicates intergradient mineral formed during firing sulphoaluminate cement clinker.Knot of the present invention, which is manufactured, to be easy, is easy to use, through the invention, doping quantity of fly ash in sulphoaluminate cement base material can be made to be up to 25 ~ 35%, reduce the dosage of sulphoaluminate cement clinker, reduce material cost, reduce pollution of the flyash to environment, guarantee and improve the intensity of sulphoaluminate cement base material, has many advantages, such as energy-saving, simple process, easy to implement.

Description

A kind of high-strength sulfoaluminate cement-based material and its preparation method

technical field

The invention relates to a high-strength sulfoaluminate cement-based material and a preparation method thereof, belonging to the field of building materials.

Background technique

Traditional Portland cement faces great challenges due to high calcination temperature and large _CO2 emissions. Compared with traditional Portland cement, sulphoaluminate cement has significantly lower calcination temperature and _CO2 emission, which is in line with the development trend of low-carbon and energy-saving cement industry, and has broad development prospects. Sulphoaluminate cement has excellent properties such as high early strength, frost resistance, impermeability, and corrosion resistance. It is mainly used in winter construction, rapid repair projects, and prefabricated components. However, as a special type of cement, sulfoaluminate cement requires high quality bauxite in raw materials, which leads to an increase in cement production costs and limits the popularization and application of sulfoaluminate cement.

Fly ash is the ashes discharged from the flue after coal combustion in thermal power generation, and is a common industrial solid waste. Adding fly ash to sulphoaluminate cement can, on the one hand, promote the resource utilization of fly ash as a building material, and on the other hand, reduce the cost of cement production. However, compared with ordinary portland cement, sulfoaluminate cement has significantly reduced calcium hydroxide in the hydration product, and the stimulation effect on the activity of fly ash is reduced. Moreover, with the increase of fly ash content, sulfur The compressive strength of aluminate cement-based cementitious materials generally decreases at different ages. Therefore, the amount of fly ash in sulphoaluminate cement is relatively low, and in actual production, it usually does not exceed 20%. Under the existing cement production technology conditions, how to ensure and improve the strength of sulphoaluminate cement-based materials under a certain amount of fly ash, or even increase the amount of fly ash on the premise of ensuring the strength of the material, is a further step. The key issue of reducing material cost and expanding its application range.

Calcium sulfosilicate ( abbreviated as ) is an intermediate mineral formed during the calcination of sulfoaluminate cement clinker. Calcium sulfosilicate will be formed only when excessive gypsum is added to the raw meal and the calcination temperature is too low. Generally, calcium sulfosilicate is considered as an inert mineral, but the applicant’s latest research found that calcium sulfosilicate can not only improve the later strength of sulfoaluminate cement, but also stimulate the potential hydraulic hardness of aluminosilicate waste slag active. Therefore, the applicant believes that calcium sulfosilicate can be used as an activator of fly ash to increase the amount of fly ash in sulfoaluminate cement and improve the performance of sulfoaluminate cement-based materials.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-strength sulphoaluminate cement-based material and its preparation method, in the case of increasing the amount of fly ash and reducing the amount of sulphoaluminate cement clinker, the strength of cement can be guaranteed and improved ,cut costs.

The purpose of the present invention is achieved in this way, a high-strength sulfoaluminate cement-based material is characterized in that it is composed of the following raw materials by weight percentage: 50-60% of sulfo-aluminate cement clinker, 25-35% of fly ash %, 5-15% of gypsum, and 5-15% of activator; the activator is calcium sulfosilicate transition mineral formed during firing sulfoaluminate cement clinker.

The calcium sulfoaluminate content in the mineral composition of the sulfoaluminate cement clinker is greater than 60%.

The fly ash is Class I fly ash or Class II fly ash.

The gypsum adopts dihydrate gypsum or natural anhydrite.

The calcium sulfosilicate transition mineral is calcined at a high temperature of 1100-1200°C from a raw meal composed of calcium carbonate, silicon dioxide, calcium sulfate dihydrate, and calcium fluoride in a mass ratio of 5.8:1.7:2.5:0.5. Prepared by incubating for 4 hours.

The mass content of calcium sulfosilicate in the activator is greater than 80%.

A method for preparing a high-strength sulphoaluminate cement-based material is characterized in that first, raw materials are prepared, and the raw materials include sulphoaluminate cement clinker, fly ash, gypsum, activator, sulphoaluminate cement clinker, powder The mass percentages of coal ash, gypsum, and activator are 50-60%, 25-35%, 5-15%, and 5-15% respectively; then the prepared raw materials are mixed and ground by a ball mill until the fineness is 0.08 mm square hole sieve with a residue of less than 2% to obtain a high-strength sulfoaluminate cement-based material; wherein, the activator is the calcium sulfosilicate transition mineral formed during the firing of sulfoaluminate cement clinker.

The invention is easy to manufacture and easy to use. Through the present invention, a high-strength sulphoaluminate cement-based material, its components are calculated by weight percentage: sulphoaluminate cement clinker 50-60%, fly ash 25-35%, gypsum 5-15%, activator 5-15%.

The applicant has analyzed the reason why the intensity of the sulphoaluminate cement mixed with fly ash decreases, because the pozzolanic activity of the fly ash is difficult to bring into play, the present invention can solve this problem by utilizing calcium sulfosilicate mineral as the activator of the fly ash pozzolanic activity a question. Calcium sulfosilicate is a transition mineral formed during the calcination of sulfoaluminate cement clinker. The applicant's latest research has found that calcium sulfosilicate can not only improve the later strength of sulfoaluminate cement, but also stimulate aluminum silicon Potential hydraulic activity of acid salt residue. Therefore, the applicant believes that calcium sulfosilicate can be used as an active stimulator of fly ash, which has an outstanding and substantial contribution to the prior art.

According to the above scheme, the calcium sulfosilicate is composed of calcium carbonate, silicon dioxide, calcium sulfate dihydrate, and calcium fluoride in a mass ratio of 5.8:1.7:2.5:0.5. It is prepared by calcination and heat preservation for 4 hours, which is more conducive to the formation of calcium sulfosilicate minerals and improves the purity. The mass content of calcium sulfosilicate in the prepared mixed mineral is greater than 80%.

Further, the calcium sulfoaluminate content in the mineral composition of the sulfoaluminate cement clinker is greater than 60%. The fly ash is Class I fly ash or Class II fly ash. The gypsum adopts dihydrate gypsum or natural anhydrite.

The preparation method of a sulphoaluminate cement-based material of the present invention comprises the following steps: mix sulphoaluminate cement clinker, fly ash, gypsum and calcium sulphosilicate in proportion through a ball mill, and grind them until fine The sieve with a degree of 0.08mm square hole is less than 2%, and the sulphoaluminate cement-based material is obtained.

The present invention has the following advantages:

1) Using calcium sulfosilicate minerals as the active stimulator of fly ash, in the case of increasing the amount of fly ash and reducing the amount of sulfoaluminate cement clinker, the strength of cement is guaranteed and improved, and the mixing of fly ash The amount can reach up to 35%, reducing the cost of cement production.

2), calcium sulfosilicate mineral is simple to prepare, and has good grindability, is suitable for industrial production, and is easy to implement as an active activator of fly ash.

3) The sulphoaluminate cement-based material prepared by the present invention has a simple process and easy-to-obtain raw materials, and can be widely used in the field of construction.

The invention can make the amount of fly ash in the sulphoaluminate cement-based material as high as 25-35%, reduces the amount of sulphoaluminate cement clinker, reduces the material cost, and reduces the pollution of the fly ash to the environment. The method guarantees and improves the strength of the sulphoaluminate cement-based material, and has the advantages of energy saving, consumption reduction, simple process, and convenient implementation.

Detailed ways

The present invention will be further described in detail below in combination with specific embodiments.

Example 1:

A high-strength sulfoaluminate cement-based material, each component is calculated by weight percentage as:

Sulphoaluminate cement clinker: 50%, Class I fly ash: 30%, dihydrate gypsum: 8%, calcium sulfosilicate: 12%;

Wherein, the calcium sulfosilicate is calcined at a high temperature of 1100-1200°C from raw meal composed of calcium carbonate, silicon dioxide, calcium sulfate dihydrate, and calcium fluoride in a mass ratio of 5.8:1.7:2.5:0.5. Prepared by incubating for 4 hours.

Weigh the raw materials of each component according to the above-mentioned predetermined mass percentage, mix them uniformly, and grind them together until the fineness is less than 2% on a square-hole sieve with a fineness of 0.08 mm, so as to obtain a sulphoaluminate cement-based material. According to the national standard GB1346-2001 "Cement Standard Consistency Water Consumption, Setting Time, Stability Test Method", GB/T17671-1999 "Cement Strength Test Method", respectively test the setting time of cement and mortar strength, the measurement results are as follows:

Example 2:

A high-strength sulfoaluminate cement-based material, each component is calculated by weight percentage as:

Sulphoaluminate cement clinker: 55%, Class I fly ash: 25%, dihydrate gypsum: 10%, calcium sulfosilicate: 10%;

Wherein, the calcium sulfosilicate is calcined at a high temperature of 1100-1200°C from raw meal composed of calcium carbonate, silicon dioxide, calcium sulfate dihydrate, and calcium fluoride in a mass ratio of 5.8:1.7:2.5:0.5. Prepared by incubating for 4 hours.

Weigh the raw materials of each component according to the above-mentioned predetermined mass percentage, mix them uniformly, and grind them together until the fineness is less than 2% on a square-hole sieve with a fineness of 0.08 mm, so as to obtain a sulphoaluminate cement-based material. According to the national standard GB1346-2001 "Cement Standard Consistency Water Consumption, Setting Time, Stability Test Method", GB/T17671-1999 "Cement Strength Test Method", respectively test the setting time of cement and mortar strength, the measurement results are as follows:

Example 3:

A high-strength sulfoaluminate cement-based material, each component is calculated by weight percentage as:

Sulphoaluminate cement clinker: 58%, Ⅱ grade fly ash: 26%, dihydrate gypsum: 8%, calcium sulfosilicate: 8%;

Wherein, the calcium sulfosilicate is calcined at a high temperature of 1100-1200°C from raw meal composed of calcium carbonate, silicon dioxide, calcium sulfate dihydrate, and calcium fluoride in a mass ratio of 5.8:1.7:2.5:0.5. Prepared by incubating for 4 hours.

Weigh the raw materials of each component according to the above-mentioned predetermined mass percentage, mix them uniformly, and grind them together until the fineness is less than 2% on a square-hole sieve with a fineness of 0.08 mm, so as to obtain a sulphoaluminate cement-based material. According to the national standard GB1346-2001 "Cement Standard Consistency Water Consumption, Setting Time, Stability Test Method", GB/T17671-1999 "Cement Strength Test Method", respectively test the setting time of cement and mortar strength, the measurement results are as follows:

By contrasting each embodiment with the blank group of the same fly ash dosage without adding calcium sulfosilicate, it can be seen that the 3d and 28d strengths of the sulfoaluminate cement-based material of the present invention are all significantly improved. Therefore, the present invention utilizes calcium sulfosilicate mineral as the active stimulator of fly ash, which not only can increase the amount of fly ash, but also helps to improve the strength of cement, and the effect is remarkable.

Claims (7)

1. A high-strength sulphoaluminate cement-based material, characterized in that it consists of the following raw materials by weight percentage: sulphoaluminate cement clinker 50-60%, fly ash 25-35%, gypsum 5-15% , 5% to 15% of the activator; the activator is the calcium sulfosilicate transition mineral formed during the firing of sulfoaluminate cement clinker. 2. A high-strength sulphoaluminate cement-based material according to claim 1, characterized in that the calcium sulphoaluminate content in the clinker mineral composition of the sulphoaluminate cement is greater than 60%. 3. A high-strength sulfoaluminate cement-based material according to claim 1, wherein the fly ash is Class I fly ash or Class II fly ash. 4. A high-strength sulfoaluminate cement-based material according to claim 1, characterized in that, said gypsum is dihydrate gypsum or natural anhydrite. 5. a kind of high-strength sulfoaluminate cement-based material according to claim 1, is characterized in that, described calcium sulfosilicate transition mineral comprises calcium carbonate, silicon dioxide, calcium sulfate dihydrate, calcium fluoride It is prepared by calcining raw meal at a mass ratio of 5.8:1.7:2.5:0.5 at a temperature of 1100-1200°C and holding it for 4 hours. 6. A high-strength sulfoaluminate cement-based material according to claim 1, characterized in that the mass content of calcium sulfosilicate in the activator is greater than 80%. 7. according to the preparation method of a kind of high-strength sulfoaluminate cement-based material described in any one of claim 1-6, it is characterized in that, at first prepare raw material, raw material comprises sulfoaluminate cement clinker, fly ash , gypsum, activator, sulphoaluminate cement clinker, fly ash, gypsum, and activator are respectively 50~60%, 25~35%, 5~15%, 5~15% by mass; then prepare The good raw materials are mixed and ground by a ball mill until the fineness is less than 2% of the 0.08mm square hole sieve, and the high-strength sulphoaluminate cement-based material is obtained; the activator is the process of firing sulphoaluminate cement clinker calcium sulfosilicate transition mineral formed in