CN106316175A - Micro-expanded retarded silicate cement - Google Patents

Abstract

The invention relates to a micro-expansion retarded Portland cement, which comprises the following components in mass percentage: Portland cement clinker: 10%-70%, industrial waste residue: 20%-80%, gypsum: 9 %-15%, organic retarding material: 0.03%-1.0%, the sum of each component is 100%; wherein, the SO in the gypsum _The weight accounts for 4.0% of the micro-expansion retarded Portland cement -8.0%. The micro-expansion retarded Portland cement of the present invention has a long setting time, initial setting time ≥ 360min, and final setting time ≥ 480min; the micro-expansion retarded Portland cement of the present invention has micro-expansion performance, and the cement paste of the present invention 7d linear expansion rate ≥ 0.1%, 28d linear expansion rate ≤ 0.8%; the micro-expansion retarded Portland cement of the present invention has added industrial waste residues, turning industrial waste residues into treasures, reducing the production cost of cement and reducing industrial waste. Environmental pollution caused by waste residues and other issues.

Description

micro-expansion retarded portland cement

technical field

The invention relates to a cement, in particular to a micro-expansion retarded portland cement.

Background technique

Cement-based stable bases are widely used in highway construction due to their advantages of high strength, good water stability, and good frost resistance. The annual demand for Portland cement used in road bases in my country is about several million tons, and there are year by year increasing trend. However, the existing Portland cement-based stable base has a large drying shrinkage coefficient, and the paved base is prone to cracking. Once the base is cracked, it will be reflected to the road surface, causing cracking of the pavement and damage to the pavement.

Studies have shown that the short initial setting time of cement, insufficient micro-expansion performance, and large fineness are the main factors affecting the cracking of cement-stabilized base materials. The micro-expansion performance of cement can reduce and compensate for the shrinkage of cement-stabilized macadam. In this way, the cracking of the base material can be effectively avoided. At the same time, in order to meet the construction time requirements of the cement-stabilized base, the initial setting time of the cement needs to be more than 6 hours.

The initial setting time of the existing Portland cement is basically less than 6 hours. The short initial setting time leads to a short delayed rolling time of cement-stabilized base materials, which adversely affects construction management and affects the quality of pavement construction; In addition, the micro-expansion performance of the existing Portland cement is poor. This is because the SO ₃ content in the existing Portland cement does not exceed 3.5%. SO ₃ can be used as the micro-expansion source of cement, and the SO ₃ content If the cement is too low, the micro-expansion effect of the cement is not enough, and it cannot achieve the effect of improving the crack resistance of the base.

Contents of the invention

The main purpose of the present invention is to provide a new type of micro-expansion retarded Portland cement. The technical problem to be solved is to make the setting time longer, so that it is more suitable for practical use.

The purpose of the present invention and the solution to its technical problems are achieved by adopting the following technical solutions. A micro-expansion retarded Portland cement proposed according to the present invention comprises the following components by mass percentage: Portland cement clinker: 10%-70%, industrial waste residue: 20%-80%, gypsum: 9%-15%, organic retarding material: 0.03%-1.0%, the sum of each component is 100%; wherein, the weight of SO in the gypsum accounts for 4.0 _% of the micro-expansion retarded Portland cement %-8.0%.

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures.

Preferably, the aforementioned micro-expansion retarded Portland cement, wherein said (calcium silicate in the Portland cement clinker accounts for the weight ≥ 66% of the Portland cement clinker.

Preferably, the aforementioned micro-expansion retarded Portland cement, wherein the weight ratio of calcium oxide to silicon oxide in the Portland cement clinker is ≥2.

Preferably, the aforementioned micro-expansion retarded Portland cement, wherein the industrial waste slag is a combination of at least two of fly ash, granulated blast furnace slag powder, steel slag powder, granulated electric furnace phosphorus slag, and coal gangue.

Preferably, the aforementioned micro-expansion retarded Portland cement, wherein the gypsum is at least one of natural gypsum and industrial by-product gypsum.

Preferably, the aforementioned micro-expansion retarded Portland cement, wherein the organic retarded material is one of carbohydrate organic retarded materials, hydroxycarboxylic acid organic retarded materials, soluble borates, and phosphates .

Preferably, the aforementioned micro-expansion retarded Portland cement, wherein the carbohydrate organic retarding material is a derivative of starch or cellulose; the hydroxycarboxylic acid organic retarding material is citric acid, tartaric acid, glucose acid, citrate, tartrate or gluconate.

Preferably, the aforementioned micro-expansion retarded Portland cement, wherein the weight percentage of cement with a fineness less than 45 μm in the micro-expansion retarded Portland cement is 70%-90%.

Preferably, the aforementioned micro-expansion retarded Portland cement, wherein said micro-expansion retarded Portland cement has an initial setting time ≥ 360min, a final setting time ≥ 480min, and a linear expansion rate of 7d cement paste ≥ 0.1%, 28d linear expansion rate ≤ 0.8%, 7d flexural strength ≥ 3.0MPa, 28d flexural strength ≥ 6.0MPa, 7d compressive strength ≥ 15.0MPa, 28d compressive strength ≥ 32.5MPa.

By virtue of the above technical solutions, the micro-expansion retarded Portland cement of the present invention has at least the following advantages:

1) The setting time of micro-expansion retarded Portland cement of the present invention is long, initial setting time ≥ 360min, final setting time ≥ 480min; Cement of the present invention takes gypsum and organic retarder as retarding material, retarding material only It is difficult to meet the requirements with gypsum. _The amount of gypsum is determined by the amount of SO3 it provides, and the setting time _of cement is not directly proportional to the SO3 content. When the SO3 content in cement is greater _than 2.5%, the setting time of cement tends to increase. It is difficult to prolong the setting time by increasing the SO ₃ content because it is stable, and the addition of organic retarding materials can increase the setting time of cement.

2) The micro-expansion retarded Portland cement of the present invention has micro-expansion properties. According to the test method of JC/T313-2009, the 7d linear expansion rate of the cement paste of the present invention is ≥ 0.1%, and the 28d linear expansion rate is ≤ 0.8%; _The weight of SO3 in the gypsum of the cement of the present invention accounts for 4.0%-8.0% of the cement, the micro-expansion source _of the cement is mainly SO3, and the SO3 content in the cement acts _on the strength and the expansion value _of the cement respectively, and the SO3 If the content is too low, the micro-expansion performance of the cement will be low, and if the SO3 content is too large, the structure _of the cement material will be destroyed and the performance of the cement material will deteriorate.

3) The micro-expansion retarded portland cement of the present invention is added with industrial waste residue, which turns waste into treasure, reduces the production cost of cement, and reduces problems such as environmental pollution caused by industrial waste residue.

The above description is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly and implement them according to the contents of the description, the preferred embodiments of the present invention will be described in detail below.

detailed description

In order to further explain the technical means and effects of the present invention to achieve the intended purpose of the invention, the specific implementation, characteristics and effects of the micro-expansion retarded Portland cement proposed according to the present invention will be described below in conjunction with the preferred embodiments. Details are as follows. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, the particular features or characteristics of one or more embodiments may be combined in any suitable manner.

The micro-expansion retarded Portland cement in the embodiment of the present invention is obtained by co-grinding Portland cement clinker, industrial waste residue, gypsum and organic retarding materials.

The embodiment of the present invention proposes a micro-expansion retarded portland cement, including the following components in mass percentage: Portland cement clinker: 10%-70%, industrial waste residue: 20%-80%, gypsum: 9%-15%, organic retarding material: 0.03%-1.0%, the sum of each component is 100%; wherein, the weight of SO in the gypsum accounts for 4.0 _% of the micro-expansion retarded Portland cement %-8.0%.

Wherein, the weight of SO in the gypsum of the cement of the present invention accounts for 4.0%-8.0% of the cement, the micro-expansion source _{of the cement is mainly SO 3 ,} and the SO content in the cement acts _on the strength and expansion value of the cement respectively simultaneously, Too low SO3 content will lead to low micro _- expansion performance _of cement, while too much SO3 content will destroy the structure of cement material and deteriorate the performance of cement material.

Preferably, the calcium silicate in the Portland cement clinker of this embodiment accounts for ≥66% by weight of the Portland cement clinker.

Preferably, the weight ratio of calcium oxide to silicon oxide in the Portland cement clinker of this embodiment is ≥2.

Preferably, the industrial waste slag in this embodiment is at least two combinations of fly ash, granulated blast furnace slag powder, steel slag powder, granulated electric furnace phosphorus slag, and coal gangue; the addition of industrial waste slag can delay the cement setting time, It also saves resources and is of great significance to the utilization of industrial waste residues.

Preferably, the gypsum in this embodiment is at least one of natural gypsum and industrial by-product gypsum.

Preferably, the organic retarding material in this embodiment is one of carbohydrate organic retarding materials, hydroxycarboxylic acid organic retarding materials, soluble borates, and phosphates.

Preferably, the carbohydrate organic retarding material of this embodiment is a derivative of starch or cellulose; the hydroxycarboxylic acid organic retarding material is citric acid, tartaric acid, gluconic acid, citrate, tartrate or glucose salt.

The cement of the present invention uses gypsum and organic retarder as the setting retarding material, and the retarding material only uses gypsum to be difficult to meet the requirements, and the amount of gypsum is determined by the amount _of SO3 provided by it, and the setting time _of cement is not related to SO3 The content is directly proportional. When the SO ₃ content in the cement is greater than 2.5%, the setting time of the cement increases steadily, and it is difficult to prolong the setting time by increasing the SO ₃ content, and the addition of organic retarding materials can increase the setting time of the cement.

Preferably, the percentage by weight of cement with fineness less than 45 μm in the micro-expansion retarded Portland cement of this embodiment is 70%-90%; if the fineness of cement is too large, the hydration of cement will be accelerated, and the setting time will be shortened. shorten.

Preferably, the initial setting time of the micro-expansion retarded Portland cement in this embodiment is ≥ 360min, the final setting time is ≥ 480min, the linear expansion rate of the cement slurry is ≥ 0.1%, the 28d linear expansion rate is ≤ 0.8%, and the 7d resistance Flexural strength ≥ 3.0MPa, 28-day flexural strength ≥ 6.0MPa, 7-day compressive strength ≥ 15.0MPa, 28-day compressive strength ≥ 32.5MPa.

In the above examples, the chemical composition of each raw material of the cement is shown in Table 1.

The chemical composition (mass percentage composition %) of each raw material of table 1 cement

"Loss" means loss on ignition, "R ₂ O" means alkali content;

"∑" indicates the sum of the first few chemical components, and the balance less than 100% is a small amount of alkaline substances or other impurities in raw materials.

In the above-mentioned examples, the ratio of raw materials of the micro-expansion retarded Portland cement in each example is shown in Table 2.

The raw material ratio (mass percentage %) of table 2 embodiment 1-6 micro-expansion retarded portland cement

Among the above-mentioned examples, the SO in the gypsum _of each embodiment accounts for the weight percent of cement, the calcium silicate in the Portland cement clinker accounts for the weight percent of the Portland cement clinker, and the SO in the Portland cement clinker The weight ratio of calcium oxide to silicon oxide and the weight percentage of cement with fineness less than 45 μm are shown in Table 3.

Table 3 Cement clinker and cement parameters

It can be known from Table ₃ that the SO3 content in gypsum accounts for 4%-8% by weight of cement, which provides the source of cement micro-expansion.

In the above examples, the cement performance testing results of each example are shown in Table 4.

Table 4 Example 1-6 micro-expansion retarded Portland cement performance test detection results

As can be seen from Table 4, the initial setting time of the slow-setting Portland cement for the road base prepared in Examples 1-6 is ≥ 360min, and the final setting time is ≥ 480min, and the setting time is greatly extended compared with general cement, which ensures the construction of the road base Delayed rolling time; 7d flexural strength ≥ 3.0MPa, 28d flexural strength ≥ 6.0MPa, 7d compressive strength ≥ 15.0MPa, 28d compressive strength ≥ 32.5MPa; cement paste 7d linear expansion rate ≥ 0.1%, The 28d linear expansion rate is ≤0.8%, which effectively compensates the cracking problem caused by the shrinkage of the base layer.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still belong to this invention. within the scope of the technical solution of the invention.

Claims (9)

1. A micro-expansion retarded Portland cement, characterized in that: it comprises each component of the following mass percentages: Portland cement clinker: 10%-70%, Industrial waste: 20%-80%, Gypsum: 9%-15%, Organic retarding materials: 0.03%-1.0%, The sum of each component is 100%; Wherein, the weight _of SO3 in the gypsum accounts for 4.0%-8.0% of the micro-expansion retarded Portland cement. 2. The micro-expansion retarded Portland cement according to claim 1, characterized in that the calcium silicate in the Portland cement clinker accounts for ≥66% of the weight of the Portland cement clinker. 3. The micro-expansion retarded Portland cement according to claim 1, characterized in that the weight ratio of calcium oxide to silicon oxide in the clinker of the Portland cement is ≥2. 4. micro-expansion retarded portland cement according to claim 1, is characterized in that, described industrial waste slag is in fly ash, granulated blast furnace slag powder, steel slag powder, granulated electric furnace phosphorus slag, coal gangue at least two combinations of . 5. The micro-expansion retarded Portland cement according to claim 1, wherein the gypsum is at least one of natural gypsum and industrial by-product gypsum. 6. The micro-expansion retarded Portland cement according to claim 1, characterized in that, the organic retarded material is carbohydrate organic retarded material, hydroxycarboxylic acid organic retarded material, soluble borate , one of the phosphates. 7. micro-expansion retarded Portland cement according to claim 6, is characterized in that, described carbohydrate organic retarded material is the derivative of starch or cellulose; Described hydroxycarboxylic acid organic retarded material is citric acid, tartaric acid, gluconic acid, citrate, tartrate or gluconate. 8. The micro-expansion retarded Portland cement according to claim 1, characterized in that the weight percentage of the cement with a fineness less than 45 μm in the micro-expansion retarded Portland cement is 70%-90%. 9. The micro-expansion retarded Portland cement according to claim 1, characterized in that the initial setting time of the micro-expansion retarded Portland cement is ≥ 360min, the final setting time is ≥ 480min, and the cement slurry is cleaned for 7 days Linear expansion rate ≥ 0.1%, 28d linear expansion rate ≤ 0.8%, 7d flexural strength ≥ 3.0MPa, 28d flexural strength ≥ 6.0MPa, 7d compressive strength ≥ 15.0MPa, 28d compressive strength ≥ 32.5MPa.