CN107382122B

CN107382122B - Cement concrete liquid additive

Info

Publication number: CN107382122B
Application number: CN201710617467.4A
Authority: CN
Inventors: 钟文慧; 杨国根; 张卫红
Original assignee: Huanggang Normal University; Ezhou Polytechnic
Current assignee: Huanggang Normal University; Ezhou Polytechnic
Priority date: 2017-07-26
Filing date: 2017-07-26
Publication date: 2020-06-16
Anticipated expiration: 2037-07-26
Also published as: CN107382122A

Abstract

The liquid additive for cement concrete consists of thiocyanate and water in the weight ratio of 21-60%. The design not only can improve the strength of the hardened cement concrete without changing the proportion of the cement concrete, but also can effectively reduce the transportation cost.

Description

Cement concrete liquid additive

Technical Field

The invention belongs to the technical field of engineering material application, and particularly relates to a thiocyanate-based cement concrete liquid additive.

Background

Nowadays, cement concrete additives are rapidly developed, and a plurality of raw materials are available for product customization at present, and the components of the cement concrete additives for improving strength mainly comprise the following types:

1) small molecule organic additives, such as triethanolamine TEA, triisopropanolamine TIPA, ethylene glycol, small molecule alcohols. The components can improve the strength of the hardened cement concrete by improving the efficiency of a mill, the proportion of active cement particles and the like in the cement production process.

2) Various synthetic polymers, such as fructose, sucrose, molasses, polycarboxylic acid concrete water reducers, calcium lignosulfonate and corresponding salts, and the like. The components can improve the strength of the cement concrete after hardening by reducing the water cement ratio in the cement concrete mixing ratio.

3) Inorganic salt additives raw materials such as chlorides, sulfates, gypsum, and the like. The components provide sodium ions, calcium ions, sulfate ions and the like required in hydration to participate in reaction in the cement hydration process, so that the hydration is accelerated, and the strength of the cement concrete after hardening is enhanced.

In the actual use process, the combination of the above components is used as a cement concrete reinforcing additive, for example, a cement grinding aid disclosed by the invention patent with the Chinese patent application publication number of CN106316190A and the application publication date of 2017, 1 month and 11 days comprises the following components in percentage by weight: 10 to 20 percent of alcohol amine compound, 1 to 5 percent of molasses, 0.5 to 3 percent of sodium sulfate, 5 to 15 percent of sodium chloride, 10 to 20 percent of sodium thiocyanate and 50 to 60 percent of water. Although the grinding aid has good effect on enhancing the early and later strength of cement, the following defects still exist:

1) the grinding aid takes alcamines compounds as main components, needs to be added in the cement production and processing process, and has strong and weak capability of increasing the strength of cement concrete, which is more dependent on the process control of the cement production process;

2) the strength of the hardened cement concrete is increased by the synthetic polymers such as molasses and the like, on one hand, the water cement ratio of the cement concrete needs to be reduced, on the other hand, the setting hardening time of the cement concrete is prolonged, and the subsequent construction is influenced;

3) the solubility of sodium sulfate and sodium chloride in water is low, the concentration of saturated solution is only 26.5 percent and 35.6 percent respectively, when the sodium sulfate and the sodium chloride are prepared into corresponding liquid additives, the moisture content in the additives is high, and thus, the transportation cost is increased; meanwhile, the cement concrete has the highest content limit to chloride ions and sulfate radicals (recorded as the content of sulfur trioxide), so that the mixing amount of the cement concrete additive containing the components is limited.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide the cement concrete liquid additive which can effectively improve the strength and the transportation efficiency of the cement concrete under the condition of not changing the proportion of the cement concrete.

In order to achieve the above purpose, the invention provides the following technical scheme:

the liquid additive for cement concrete consists of thiocyanate and water in the weight ratio of 21-60%.

The raw material composition of the additive also comprises 10-25% of micromolecular alcohol amine by mass percentage.

The additive also comprises micromolecular alcohol amine and saccharides, wherein the thiocyanate is 21-50% by mass, the micromolecular alcohol amine is 10-15% by mass, and the saccharides are 15-30% by mass.

The micromolecular alcohol amine is triethanolamine.

The saccharide is at least one of fructose, sucrose, corn syrup, glucose or sodium gluconate.

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

1. the raw material composition of the cement concrete liquid additive comprises 21-60% of thiocyanate and water, and on one hand, the strength of the hardened cement concrete can be effectively improved by adopting the single-component aqueous solution of the thiocyanate without changing the water-cement ratio condition of the cement concrete; on the other hand, the solubility of the thiocyanate in water at normal temperature reaches 60%, and the mixing amount limitation does not exist, so that the transportation efficiency of the additive can be obviously improved, and the transportation cost is reduced; meanwhile, the additive can be added in the cement production and processing process and the cement using process, namely the cement concrete preparation process, and the reinforcing performance of the additive is not influenced by the cement production process. Therefore, the invention not only can improve the strength of the hardened cement concrete without changing the proportion of the cement concrete, but also can reduce the transportation cost.

2. The cement concrete liquid additive also comprises micromolecular alcohol amine and saccharides, the strength of the hardened cement concrete can be further improved by adding the micromolecular alcohol amine, and the solubility of thiocyanate can be increased by compounding the micromolecular alcohol amine and the thiocyanate, so that the preparation of a high-concentration additive is facilitated, and the transportation cost is reduced; in addition, the combination of the saccharides and the micromolecular alcohol amine can promote the strengthening effect of the micromolecular alcohol amine, so that the strength of the cement concrete after hardening is improved. Therefore, the invention further improves the strength of the hardened cement concrete and reduces the transportation cost.

Detailed Description

The present invention will be further described with reference to the following embodiments.

The micromolecular alcohol amine is triethanolamine.

The principle of the invention is illustrated as follows:

the invention provides a new inorganic salt cement concrete additive-thiocyanate solution which can improve the strength of the hardened cement concrete by 20 percent under the condition of not changing the water cement ratio of the cement concrete. Compared with the existing additives, the additive has the following advantages:

1. the thiocyanate has higher solubility in water, can be dissolved in an organic solvent, and can still improve the effective content when being compounded with organic matters, so that the transportation efficiency of the liquid admixture can be effectively improved;

2. at present, the content of thiocyanate in cement concrete is not limited, so that the problem of mixing amount limitation caused by the content of thiocyanate does not exist.

Example 1:

the liquid additive for cement concrete consists of thiocyanate and water in the weight ratio of 21%.

Example 2:

the difference from example 1 is that:

the mass percentage content of the thiocyanate is 30%.

Example 3:

the difference from example 1 is that:

the mass percentage content of the thiocyanate is 40%.

Example 4:

the difference from example 1 is that:

the mass percentage content of the thiocyanate is 50%.

Example 5:

the difference from example 1 is that:

the mass percentage content of the thiocyanate is 60%.

Example 6:

the difference from example 2 is that:

the additive also comprises triethanolamine as a raw material, and the triethanolamine accounts for 10% by mass.

Example 7:

the difference from example 6 is that:

the triethanolamine accounts for 15 percent by mass.

Example 8:

the difference from example 6 is that:

the triethanolamine accounts for 25 percent by mass.

Example 9:

the difference from example 6 is that:

the raw material composition of the additive also comprises sucrose, and the mass percent content of the sucrose is 15%.

Example 10:

the difference from example 9 is that:

the mass percentage content of the sucrose is 20%.

Example 11:

the difference from example 9 is that:

the mass percentage content of the sucrose is 30%.

In order to examine the effect of the additive disclosed by the invention on the strength of hardened cement concrete, the formulations disclosed in examples 2, 4 and 9 and conventional additives are respectively added into water for cement mortar, and a strength test is carried out according to GB/T17671-1999 method for testing the strength of cement mortar (ISO method), and a blank group is set. Wherein, the cement used for the strength test adopts the reference cement for the cement concrete admixture, the sand adopts the standard sand produced by Xiamen Escio company Limited, the mass percent content of the chloride salt in the conventional additive is 15-20%, the mass percent content of the micromolecular alcohol amine is 5-10%, the mass percent content of the molasses is 20-30%, and the rest is water.

Because the addition amount of the additive is low, the requirement on weighing equipment is high, and in order to ensure the accuracy of the addition amount, the addition method is changed as follows: diluting an additive and water into a dilute solution according to the proportion of 1:99, calculating the using amount of the required dilute solution according to the required mixing amount of the additive, weighing, finally adding water to 225g of standard water required by GB/T17671-1999 Cement mortar Strength test method (ISO method), and performing other test steps according to GB/T17671-1999 Cement mortar Strength test method (ISO method). The results are shown in Table 1:

table 1 strength test results

As can be seen from the above test data, the additive of the present invention exhibits a good reinforcing effect not lower than that of the conventional additive, and the reinforcing effect is more prominent with the addition of triethanolamine and sucrose.

Claims

1. A cement concrete liquid additive is characterized in that: the additive comprises the raw materials of 21-50% by mass of thiocyanate, 10-15% by mass of triethanolamine and 15-30% by mass of saccharide.

2. A cement concrete liquid additive according to claim 1, characterized in that: the mass percentage content of the thiocyanate is 40-50%.

3. A cement concrete liquid additive according to claim 1, characterized in that: the saccharide is at least one of fructose, sucrose, molasses, glucose or sodium gluconate.