Early strength agent for super-sulfated cement concrete and application thereof

Abstract

This invention relates to an early-strength agent for hypersulfate cement concrete and its application, belonging to the field of building materials. The early-strength component of the hypersulfate cement comprises, by weight, the following components: 70-80 parts C-S-H / PCE, 15-25 parts sodium hydroxide or sodium carbonate, 5-10 parts sodium lactate, and 10-20 parts lithium carbonate. This invention solves the problem of long setting time of hypersulfate cement and slow early strength development of the prepared concrete, and plays a positive role in promoting the application of hypersulfate cement.

Description

Technical Field

[0001] This invention belongs to the field of building materials and relates to an early-strength agent for supersulfate cement concrete and its application. Background Technology

[0002] Supersulfate cement, also known as supersulfate cement, is mainly composed of slag, gypsum, and calcium hydroxide (or cement clinker). Supersulfate cement possesses excellent low-carbon and environmentally friendly properties, but its slow hydration and low early strength limit its widespread application in engineering. Currently, there are many technical approaches to improve the early strength of silicate cement concrete, which is widely used in engineering, including some early-strength agents such as chloride salts, sulfates, and alkanolamines. However, because the hydration reaction type and hydration products are completely different from those of silicate cement, existing early-strength agents cannot be used to increase the early strength of supersulfate cement. Therefore, it is necessary to develop specialized early-strength components to prepare early-strength supersulfate cement.

[0003] The supersulfate cement targeted by this invention can make large-scale use of industrial by-products such as granulated blast furnace slag powder and chemical gypsum. It is a low-carbon and environmentally friendly cementitious material. This invention provides an efficient, economical and sustainable solution to problems such as construction delays caused by insufficient early strength in building engineering. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an early strength agent for supersulfate cement concrete and its application.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides an early-strength agent for supersulfate cement concrete, wherein the early-strength agent is composed of the following materials in parts by weight: CSH / PCE: 70-80 copies; Sodium hydroxide or sodium carbonate: 15-25 parts; Sodium lactate: 5-10 parts; Lithium carbonate: 10-20 parts.

[0006] Preferably, the CSH / PCE component is composed of the following parts by weight of materials: Siliceous materials: 10-50 parts, any one of silica fume, sodium silicate, and silicon acetate; Calcium-rich materials: 30-150 parts, any one of calcium hydroxide, calcium nitrate, and calcium sulfate; PCE: 5 to 25 parts, any one or more of polycarboxylic acid ethers, polycarboxylic acid esters, or polycarboxylic acid-polyether copolymers.

[0007] Preferably, the CSH / PCE component is prepared as follows: The silicon material, calcium material and PCE were reacted under microwave power of 600W~800W for 30~60 seconds; The obtained CSH / PCE aqueous solution was dried to a powder form to prepare the product. Furthermore, the application of the early-strength agent of the supersulfate cement concrete in the preparation of early-strength supersulfate cement; Furthermore, the present invention provides an early-strength supersulfate cement, wherein the early-strength supersulfate cement is prepared by comprising the early-strength agent of the supersulfate cement concrete; Furthermore, the application of the supersulfate cement concrete accelerator in the preparation of early-strength slag cement concrete.

[0008] Furthermore, the present invention provides an early-strength slag cement concrete, wherein the early-strength slag cement concrete is prepared by comprising the early-strength agent of the supersulfate cement concrete.

[0009] The beneficial effects of this invention are as follows: This invention addresses the technical challenges of long setting time and slow early strength development in concrete prepared with persulfate cement by providing a specialized early strength agent. This agent significantly enhances the early strength of persulfate cement concrete under room temperature curing conditions, thereby effectively shortening the construction cycle and solving the problem of construction delays caused by insufficient early strength.

[0010] When the early-strength agent prepared in this invention is added at a dosage of 4%, compared with the baseline group without early-strength agent, the 1-day flexural strength is increased by 176%~223%; the 1-day compressive strength is increased by 74%~94%. The 28-day strength still maintains an increasing trend, and no strength reduction phenomenon is observed, indicating that the early-strength agent has no adverse effect on the later strength development.

[0011] The early-strength agent prepared by this invention has good applicability; it can be incorporated into cement to prepare early-strength supersulfate cement, or into concrete to prepare early-strength slag cement concrete, providing flexible application solutions for different engineering scenarios. It plays a positive role in promoting the application of supersulfate cement.

[0012] In summary, this invention effectively overcomes the deficiency of early strength in supersulfate cement and plays a positive role in promoting its application in the field of low-carbon and environmentally friendly building materials.

[0013] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Detailed Implementation

[0014] Example 1 One early strength agent component is hydrated calcium silicate-polycarboxylate ether (CSH / PCE): (1) Weigh 10 to 50 parts by mass of siliceous material, including any one of silica fume, sodium silicate, and silicon acetate, and 30 to 150 parts by mass of calcareous material, including any one of calcium hydroxide, calcium nitrate, and calcium sulfate, and 5 to 25 parts by mass of any one or more of polycarboxylic acid ether, polycarboxylic acid ester, or polycarboxylic acid-polyether copolymer. (2) Silica materials, calcium materials and polycarboxylic acid substances are mixed in proportion, and then mixed with 2 to 5 times the amount of water and placed in a water bath or microwave at high temperature to synthesize an aqueous solution of CSH / PCE components; (3) The obtained CSH / PCE component aqueous solution was dried to obtain powdered CSH / PCE.

[0018] Example 2 An early-strength agent suitable for supersulfate cement: Weigh 70-80 parts by mass of powdered CSH / PCE, 15-25 parts by mass of sodium hydroxide or sodium carbonate, and 5-10 parts by mass of sodium lactate. Mix them thoroughly and then dry them completely.

[0019] Example 3 A type of early-strength supersulfate cement: (1) Prepare supersulfate cement as a reference cementitious material by uniformly mixing 70 parts by mass of finely ground slag, 20 parts by mass of finely ground gypsum and 5 parts by mass of finely ground clinker.

[0020] (2) Using the above reference cementitious materials, refer to the test method of silicate cement and prepare cement mortar specimens with a water-cement ratio of 0.50 and a mortar-mortar ratio of 1:3.

[0021] (3) Prepare different early strength agents according to the components in the table below.

[0022] Table 1. Components of Early Strength Agent Serial Number CSH / PCE Sodium carbonate Sodium hydroxide Sodium lactate lithium carbonate ESA-0 0 0 0 0 0 ESA-1 70 25 0 5 10 ESA-2 75 20 0 5 10 ESA-3 80 0 20 10 10 ESA-4 80 0 20 10 20 ESA-5 75 5 15 5 20 (4) The above 6 groups of early strength agents were used to form mortar specimens at a water-cement ratio of 0.50 according to a weight percentage of 4%. After standing for 24 hours, the specimens were demolded and their compressive strength at 3d, 7d and 28d was tested, as shown in the table below.

[0023] Table 2. Strength test results of specimens after incorporation of early-strength agent.

[0024] The results in the table show that when the dosage of the early strength agent is 4%, the flexural strength of the five early strength agents in Table 1 increased by 176%-223% and the compressive strength increased by 74%-94% after 1 day compared with the benchmark. The strength after 28 days still showed an increasing trend. The invented supersulfate cement concrete early strength agent has excellent performance.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An early-strength agent for supersulfate cement concrete, characterized in that, The early strength agent is composed of the following materials in parts by weight: CSH / PCE: 70-80 copies; Sodium hydroxide or sodium carbonate: 15-25 parts; Sodium lactate: 5-10 parts; Lithium carbonate: 10-20 parts.

2. The early-strength agent for supersulfate cement concrete according to claim 1, characterized in that, The CSH / PCE component is composed of the following parts by weight: Siliceous materials: 10-50 parts, any one of silica fume, sodium silicate, and silicon acetate; Calcium-rich materials: 30-150 parts, any one of calcium hydroxide, calcium nitrate, and calcium sulfate; PCE: 5 to 25 parts, any one or more of polycarboxylic acid ethers, polycarboxylic acid esters, or polycarboxylic acid-polyether copolymers.

3. The early-strength agent for supersulfate cement concrete according to claim 2, characterized in that, The CSH / PCE component is prepared as follows: The silicon material, calcium material and PCE were reacted under microwave power of 600W~800W for 30~60 seconds; The obtained CSH / PCE aqueous solution was dried to form a powder.

4. Application of early-strength agents for hypersulfate cement concrete in the preparation of early-strength hypersulfate cement.

5. Early-strength supersulfate cement, characterized in that: The early-strength supersulfate cement is prepared by comprising the early-strength agent of supersulfate cement concrete according to any one of claims 1-3.

6. Application of early-strength agents for supersulfate cement concrete in the preparation of early-strength slag cement concrete.

7. Early-strength slag cement concrete, characterized in that: The early-strength slag cement concrete is prepared by using the early-strength agent of the supersulfate cement concrete according to any one of claims 1-3.

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