CN110698102A

CN110698102A - Marine admixture

Info

Publication number: CN110698102A
Application number: CN201911054264.4A
Authority: CN
Inventors: 康明; 周维; 曹黎颖
Original assignee: Shanghai Baotian New Building Materials Co Ltd
Current assignee: Shanghai Baotian New Building Materials Co Ltd
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2020-01-17
Also published as: WO2021082105A1; SG11202011435VA

Abstract

The invention belongs to the technical field of ocean engineering materials, and particularly relates to a marine admixture which comprises the following components in parts by weight: 50-90 parts of slag micro powder, 10-50 parts of fly ash and 1-10 parts of excitant are mixed according to a certain proportion and then stirred uniformly to obtain the composite material. The density of the concrete material can be improved by using the marine admixture, a low-permeability, high-compactness and low-defect concrete structure is formed, the corrosion resistance of the concrete structure in the sea is fundamentally improved, and the carbonization resistance, permeation resistance and frost resistance of the concrete are improved; and the solid waste is used as the main raw material, so that the method has positive significance for resource regeneration and environmental protection, and meanwhile, the raw material is easy to obtain, the preparation process is simple, and the process is controllable.

Description

Marine admixture

Technical Field

The invention relates to the technical field of marine engineering materials, in particular to a marine admixture.

Background

The influence of the seawater environment on the corrosion resistance and the durability of ocean engineering facilities is huge, and sea filling and land making and basic engineering construction are carried out in coastal areas, and the ocean engineering facilities face severe weather environments such as high temperature, high humidity, high salt fog, large water depth and the like, which puts very high requirements on the performance of ocean engineering building materials. However, ordinary portland cement has poor corrosion resistance, high hydration heat, and since the early tensile strength of concrete is low and the elastic modulus is small, it easily causes severe temperature cracking in concrete, especially in mass concrete, thereby seriously affecting the strength and durability of marine engineering structures.

Under the marine environment, the coupling effect of multiple factors such as a temperature field, a humidity field, harmful ion corrosion, super strong typhoon and the like causes serious damage to the safety service and the durability of a concrete structure, so that the service life of the concrete building is far lower than the expected value of the standard design. The most serious and common durability problems faced by marine cement concrete at home and abroad are cement-based material corrosion, erosion and corrosion of steel bars caused by chlorine. Instability of hydration products in seawater is a difficult problem of the existing portland cement (OPC) for ocean engineering structures in research and application.

Both the portland cement hydration products Calcium Hydroxide (CH) and Calcium Silicate Hydrate (CSH) gel are susceptible to corrosion or erosion in seawater media. The clinker composition is adjusted, and the auxiliary cementing material is introduced in a large amount to reduce hydration heat, improve corrosion resistance and retard Cl^-But still does not overcome the product stability problem. Early studies at the university of berkeley, california, showed that reducing the CH proportion in the cement product, while introducing aluminum components into the CSH gel to produce Calcium Aluminum Silicate (CASH) gel, significantly improved its resistance to seawater erosion. Research in europe on marine structures with millennium history in ancient romans has shown that the formation of stable zeolite-like products in seawater in the cement is a significant cause of its long-term erosion resistance. The research suggests that the introduction of a stable product in a seawater medium is an important way for developing a high-corrosion-resistance cementing material, the maritime work cement standard is established in Norway, America, Lafaji and China at present, andproduction and engineering applications. The marine construction environment is severe and the special cement admixture is lacked, which causes poor construction quality and Cl shortage in service^-The rapid on-line detection technology causes poor durability of ocean engineering. Therefore, the special additive and the on-site nondestructive Cl are developed^-Measurement, early steel corrosion diagnosis techniques and long-term service performance detection are major trends in the field.

Disclosure of Invention

Based on the existing research and development experience and inspiration of cement-based marine materials at home and abroad, the marine Portland cement with high corrosion resistance, high strength and stable long-term performance is developed by taking stable products and composite chlorine resistance in a seawater medium as the core to meet the requirement of marine engineering durability.

The above object of the present invention is achieved by the following technical solutions:

in a first aspect, the marine admixture of the present invention comprises the following raw materials in parts by weight: 50-90 parts of slag micro powder, 10-50 parts of fly ash or 1-10 parts of excitant, and the slag micro powder is obtained by mixing the raw materials according to a ratio and then uniformly stirring.

In certain embodiments, the marine admixture comprises the following raw materials in parts by weight: 55-80 parts of slag micro powder, 15-40 parts of fly ash and 1-8 parts of excitant. The slag micro powder and the fly ash are reasonably mixed, and the mixture is used for the concrete for ocean engineering, can effectively reduce the hydration heat of the concrete, reduce the temperature cracks of the concrete and improve the durability of the concrete. The addition of the excitant can play the roles of exciting activity, improving early strength and the like.

The slag micro powder is S95 grade, and the specific surface area is 400-450 m²/kg, preferably having a specific surface area of 420m²/kg。

The fly ash meets the requirements of GB/T1596-2017 fly ash used in cement and concreteThe related technical indexes of the health-care product comprise that the water content is less than or equal to 1.0 percent, and SO₃The content is less than or equal to 3.0 percent.

The excitant is one or a mixture of more than two of triisopropanolamine, triethanolamine, glycol, desulfurized gypsum, calcium oxide and sodium sulfate.

Further, the desulfurized gypsum is power plant desulfurized gypsum or sintered desulfurized gypsum.

In one embodiment, the marine admixture has a specific surface area of 420m of 60 parts by weight²The material consists of per kg of S95-grade slag micro powder, 35 parts of fly ash and 5 parts of desulfurized gypsum.

In one embodiment, the marine admixture has a specific surface area of 420m calculated by weight parts of 65 parts²The coal ash consists of per kg of S95-grade slag micro powder, 32 parts of fly ash and 3 parts of sodium sulfate.

In one embodiment, the marine admixture has a specific surface area of 420m of 70 parts by weight²The material consists of per kg of S95-grade slag micro powder, 22 parts of fly ash, 5 parts of desulfurized gypsum and 3 parts of sodium sulfate.

In a second aspect, the concrete for ocean engineering is C30 grade, comprises any one of the marine admixtures, 30-35% of the total weight of the concrete, and further comprises cement, medium sand, stones, an additive and water.

In one embodiment, the marine admixture is added in an amount of 33% by weight based on the total weight of the concrete.

Compared with the prior art, the invention has the beneficial effects that:

1. the marine admixture is prepared by taking metallurgical solid wastes such as slag micro powder, fly ash and the like as main raw materials and adding a proper amount of excitant material according to a certain proportion, so that the cement dosage is reduced, the hydration heat of concrete is effectively reduced, the temperature crack of the concrete is reduced, and the durability of the ocean engineering concrete such as sulfuric acid resistance, chlorine ion resistance and the like is improved.

2. The marine admixture can improve the density of concrete materials, form a low-permeability, high-compactness and low-defect concrete structure, fundamentally improve the corrosion resistance of the concrete structure in the ocean, and improve the carbonization resistance, permeation resistance and frost resistance of the concrete.

3. The invention can improve the early strength and improve the working performance of the concrete by adding the excitant.

4. The marine admixture takes solid waste as a main raw material, has positive significance for resource regeneration and environmental protection, and is controllable in product processing technology and convenient to implement.

Detailed Description

The invention will now be further illustrated by reference to the following examples:

the marine admixture prepared in the following examples comprises the following raw materials in parts by weight: 50-90 parts of slag micro powder, 10-50 parts of fly ash and 1-10 parts of excitant, and the slag micro powder is obtained by compounding the raw materials according to a proportion and then uniformly stirring;

the slag micro powder is S95 grade, and the specific surface area is 400-450 m²/kg。

The fly ash meets the related technical indexes of GB/T1596-2017 fly ash for cement and concrete, the water content is less than or equal to 1.0 percent, and SO₃The content is less than or equal to 3.0 percent.

The exciting agent is one or more of triisopropanolamine, triethanolamine, ethylene glycol, desulfurized gypsum, calcium oxide and sodium sulfate.

The desulfurized gypsum is power plant desulfurized gypsum or sintered desulfurized gypsum.

As further explained in the following by examples 1 to 3, the marine admixture is obtained by adding the raw materials into a stirring device according to the following mixture ratio, stirring for 4 minutes and uniformly mixing, and the difference is that:

example 1

The specific surface area is 420m in parts by weight²60 parts of S95-grade slag micro powder per kg, 35 parts of fly ash and 5 parts of desulfurized gypsum.

Example 2

The specific surface area is 420m in parts by weight²65 parts of S95-grade slag micropowder/kg, 32 parts of fly ash and 3 parts of sodium sulfate.

Example 3

The specific surface area is 420m in parts by weight²70 parts of S95-grade slag micro powder per kg, 22 parts of fly ash, 5 parts of desulfurized gypsum and 3 parts of sodium sulfate.

Test data

The prepared marine admixture is used for carrying out a concrete test, the concrete is designed to be C30 grade, the mixing proportion of common pump concrete is selected, the water consumption is basically unchanged, the concrete slump is controlled to be 180 +/-30 mm by adjusting the mixing amount of the admixture, and the mixing proportion of C30 grade concrete is shown in Table 1, wherein:

comparative example 1 is a reference concrete.

Comparative example 2 is a base concrete having a raw material composition to which a specific surface area of 420m was added²The slag powder of S95 level per kg, and the using amount of cement is correspondingly reduced.

The effect examples 1 to 3 are that the marine admixture obtained in the examples 1 to 3 is added to the raw material composition of the standard concrete, and the addition amount is 33% of the cementing material, and the cement usage amount is correspondingly reduced.

The mechanical properties of the concrete are shown in table 2, the endurance quality of the concrete is measured and calculated according to GB/T50082-2009 Standard test method for the long-term performance and the endurance performance of the common concrete, and the result is shown in tables 3-6.

Table 1: mixing ratio/kg of C30 grade concrete

Table 2: mechanical properties of concrete

As can be seen from Table 2, the compressive strength of the concrete doped with the marine admixture (effect examples 1-3) is slightly lower than that of the reference concrete (comparative example 1) at the early stage, and gradually exceeds that of the reference concrete at the later stage, so that the flexural strength is close to that of the reference concrete.

The concrete shrinkage resistance is tested according to GB/T50082-2009, and concrete shrinkage values of different ages are respectively tested, and the results are shown in Table 3.

Table 3: dry shrinkage resistance of concrete

Dry shrinkage factor/. times.10^-6	Comparative example 1	Comparative example 2	Effect example 1	Effect example 2	Effect example 3
						1d	65.23	53.26	34.93	34.85	35.65
3d	126.12	112.70	91.55	88.04	82.15
						7d	174.95	164.94	122.04	130.82	135.69
14d	216.28	194.77	173.75	172.10	173.66
						28d	246.73	214.82	203.08	204.75	211.04
45d	263.48	226.56	208.66	208.87	221.95
						60d	276.67	238.14	215.68	214.01	225.96

As can be seen from Table 3, the dry shrinkage of the concrete doped with the marine admixture (effect examples 1-3) is obviously lower than that of the reference concrete (comparative example 1) and slightly better than that of the slag micropowder concrete (comparative example 2) with the same doping amount, which indicates that the marine admixture is beneficial to reducing the early shrinkage of the concrete.

Reference GB/T50082-2009 test pieces of standard maintenance 28d were subjected to carbonation tests. CO in the carbonization tank₂The concentration is 20%, the temperature is 20 +/-3 ℃, and the relative humidity is 70% +/-5%. The test results are shown in table 4.

Table 4: results of C30 concrete anti-carbonation test

Test items	Comparative example 1	Comparative example 2	Effect example 1	Effect example 2	Effect example 3
						14d carbonization depth (mm)	3.2	2.9	3.0	2.7	2.7
28d carbonization depth (mm)	5.7	5.1	5.2	4.2	4.9
						60d carbonization depth (mm)	8.2	7.0	5.9	5.4	6.0

As can be seen from Table 4, compared with the reference concrete (comparative example 1), the carbonization depth of the concrete doped with the marine admixture (effect examples 1-3) is reduced to different degrees, and the reduction trend is more obvious along with the continuation of the carbonization time, which shows that the anti-carbonization performance of the concrete can be improved to a certain extent by doping the marine admixture.

The test results of the water depth resistance and the chloride ion electric flux resistance of the test pieces after the concrete curing for 28d are shown in Table 5.

Table 5: concrete water penetration resistance test and chloride ion penetration resistance result

Test items	Comparative example 1	Comparative example 2	Effect example 1	Effect example 2	Effect example 3
						Height of water penetration (mm)	7.2	6.9	5.6	5.2	6.4
Electric flux (C)	2244	2062	1550	1201	1892

As can be seen from Table 5, the concrete impermeability was significantly improved when the admixture for marine use was incorporated.

After the mortar test block is soaked in a 10% sulfate solution for a corresponding age period, the compression strength and the breaking strength of the test piece are shown in a table 6.

Table 6: compression strength and rupture strength ratio of soaked mortar test piece in sulfate solution

Test items	Comparative example 1	Comparative example 2	Effect example 1	Effect example 2	Effect example 3
						3d compressive strength ratio%	104	105	102	109	107
3d breaking strength ratio%	104	105	116	120	114
						7d compressive strength ratio%	109	113	108	122	118
7d flexural strength ratio%	109	115	120	120	128
						28d compressive strength ratio%	102	102	106	101	103
28d flexural strength ratio%	113	110	124	116	119
						60d compressive strength ratio%	103	101	107	102	105
60d flexural strength ratio%	100	103	109	108	102

As can be seen from Table 6, the mortar specimens immersed in the sulfate solution had higher compressive and flexural strengths than the specimens cured in tap water at the same formulation.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention, and the present invention should not be limited by the disclosure of the preferred embodiments. Therefore, it is intended that all equivalents and modifications which do not depart from the spirit of the invention disclosed herein are deemed to be within the scope of the invention.

Claims

1. The marine admixture is characterized by comprising the following components in parts by weight: 50-90 parts of slag micro powder, 10-50 parts of fly ash or 1-10 parts of excitant, and the slag micro powder is obtained by mixing the raw materials in proportion and then uniformly stirring; wherein the slag micro powder is S95 grade, and the specific surface area is 400-450 m²/kg。

2. The marine admixture of claim 1 wherein said admixture comprises in parts by weight: 55-80 parts of slag micro powder, 15-40 parts of fly ash and 1-8 parts of excitant.

3. According to the rightThe marine admixture according to claim 1 or 2, wherein said fine slag powder is grade S95, and has a specific surface area of 420m²/kg。

4. The marine admixture according to claim 1 or 2, wherein said fly ash meets the technical specifications of GB/T1596-2017 fly ash for use in cement and concrete, the water content is less than or equal to 1.0%, SO₃The content is less than or equal to 3.0 percent.

5. Marine admixture according to claim 1 or 2, wherein the excitant is selected from one or a mixture of two or more of triisopropanolamine, triethanolamine, ethylene glycol, desulfurized gypsum, calcium oxide, sodium sulphate; wherein the desulfurized gypsum is power plant desulfurized gypsum or sintered desulfurized gypsum.

6. Marine admixture according to any one of claims 1 to 5, characterised in that the amount of said admixture is 60 parts by weight per specific surface area 420m²The material consists of per kg of S95-grade slag micro powder, 35 parts of fly ash and 5 parts of desulfurized gypsum.

7. Marine admixture according to any one of claims 1 to 5, characterised in that the amount of the admixture is 65 parts by weight per 420m of specific surface area²The coal ash consists of per kg of S95-grade slag micro powder, 32 parts of fly ash and 3 parts of sodium sulfate.

8. Marine admixture according to any one of claims 1 to 5, characterised in that the amount of said admixture is 70 parts by weight per 420m of specific surface area²The material consists of per kg of S95-grade slag micro powder, 22 parts of fly ash, 5 parts of desulfurized gypsum and 3 parts of sodium sulfate.

9. The concrete for ocean engineering is characterized by being of C30 grade, comprising the marine admixture of any one of claims 1-8, and the admixture accounts for 30-35% of the total weight of the concrete, and further comprising cement, medium sand, stones, an additive and water.

10. The concrete for ocean engineering according to claim 9, wherein the marine admixture according to any one of claims 1 to 8 is added in an amount of 33% by weight based on the total weight of the concrete.