High-calcium fly ash concrete

A technology of high-calcium fly ash and low-calcium fly ash, applied in the direction of sustainable waste treatment, solid waste management, climate sustainability, etc., can solve the problem of increased corrosion of cement concrete steel bars, alkali-aggregate reaction or sulfate corrosion risk, high-calcium ash is easy to form agglomerates, and reduces stability, etc., to achieve the effects of eliminating poor stability, improving resource utilization, and saving resources

Active Publication Date: 2010-12-01
CHINA STATE CONSTR READY MIXED CONCRETE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] 1) Aging water spraying, this method utilizes CO in the air through long-term aging 2 React with moisture and f-CaO in high calcium fly ash to reduce or eliminate f-CaO to achieve the purpose of reducing or eliminating stability. However, this method takes a long time and is not suitable for ready-mixed concrete production enterprises. In other words, the powder is stored in a closed barrel, so the operability is not strong. In addition, because the high-calcium ash is self-hardening, the high-calcium ash processed by this method is easy to form agglomerates, and it is not suitable for use as a concrete admixture. ;
[0007] 2) chemical excitation, which is to excite an activator (such as an alkaline substance: NaOH, Ca(OH) 2 , alkali metal salt: Na 2 CO 3 、Na 2 SO 4 , CaSO 4 etc.) After being added to cement concrete, the chemical activity of high-calcium fly ash is improved and the stability of high-calcium fly ash is reduced through the "variety effect" and "excitation effect". However, a large amount of alkali metal ions introduced by it Or sulfate ions, will increase the alkali metal content in the prepared cement concrete, thereby increasing the risk of steel corrosion, alkali aggregate reaction or sulfate attack in cement concrete;
[0008] 3) Mechanical activation. In this method, the high-calci

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～4

[0049] A high-calcium fly ash concrete, the weight ratio of each raw material is shown in Table 2.

[0050] The weight ratio of each raw material in Table 2 (kg / m 3 )

[0051]

[0052] in:

[0053] temporarily hard water The concentration is 630mg / L;

[0054] The free calcium oxide content of high calcium fly ash is 3.2%;

[0055] The cement is ordinary Portland cement with a strength grade of 42.5;

[0056] The gravel is continuously graded from 5 to 31.5mm, and the mud content is 2%;

[0057] The sand is river sand, the fineness modulus is 2.0, and the mud content is 3%;

[0058] The water reducer is a polycarboxylate water reducer with a solid content of 20% and a water reducing rate of 23%.

[0059] According to the weight ratio of mixing water, cement and high-calcium fly ash in Table 2, mix the mixing water, cement and high-calcium fly ash into a slurry, and then follow the "Cement Standard Consistency Water Consumption, Setting Time, and Stability" Test meth...

Embodiment 5～7

[0066] A high-calcium fly ash concrete, the weight ratio of each raw material is shown in Table 4.

[0067] Each raw material weight ratio of table 4 (kg / m 3 )

[0068] Numbering

mixing water

cement

High Calcium Fly Ash

gravel

sand

Superplasticizer

Example 5

158

405

45

1070

713.4

9.0

Example 6

158

360

90

1070

713.4

9.0

Example 7

158

315

135

1070

713.4

9.0

[0069] in:

[0070] The mixing water is temporarily hard water, The concentration is 1270mg / L;

[0071] The calcium oxide content of high calcium fly ash is 9.3%;

[0072] The cement is Portland cement with a strength grade of 42.5;

[0073] The gravel is continuously graded from 5 to 31.5mm, and the mud content is 1.4%;

[0074] The sand is river sand with a fineness modulus of 2.8 and a mud content of 1.7%;

[0075] The water reducer is a polycarboxylate water reduc...

Embodiment 8～10

[0080] A high-calcium fly ash concrete, the weight ratio of each raw material is shown in Table 6.

[0081] Table 6 The weight ratio of each raw material (kg / m 3 )

[0082]

[0083] in:

[0084] The mixing water is temporarily hard water, The concentration is 350mg / L;

[0085] The free calcium oxide content of high calcium fly ash is 1.5%;

[0086] The cement is ordinary Portland cement with a strength grade of 42.5;

[0087] The gravel is continuously graded from 5 to 31.5mm, and the mud content is 0.7%;

[0088] The sand is river sand with a fineness modulus of 2.6 and a mud content of 2.5%;

[0089] The water reducing agent is a naphthalene-based water reducing agent with a solid content of 33% and a water reducing rate of 18.7%;

[0090] Low-calcium fly ash is Class II fly ash with a water requirement ratio of 104%.

[0091] Slag powder, that is, granulated blast furnace slag powder is S95 grade slag powder, with a specific surface area of ​​400m 2 / kg.

[00...

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Abstract

The invention belongs to the technical field of building materials, particularly relating to high-calcium fly ash concrete. The high-calcium fly ash concrete comprises the following raw materials by weight in per cubic meter of concrete: 144-175 kg of mixing water, 224-480 kg of cement, 35-135 kg of high-calcium fly ash, 1007-1120 kg of gravels, 671-804 kg of sand, 1.7-9 kg of water reducing agents, 0-110 kg of low-calcium fly ash and 0-110 kg of slag powder, wherein the mixing water is temporary hardwater, and the concentration of HCO3<-> in the mixing water is greater than 300 mg/L. The concrete has the characteristics of easy production and high operability, the high-calcium fly ash resource can be fully utilized, and the poor stability is eliminated.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a high-calcium fly ash concrete. Background technique [0002] Fly ash is a kind of industrial waste from thermal power plants. It is the waste residue discharged from the flue after the combustion of finely ground coal, commonly known as "fly ash". Fly ash is an artificial pozzolanic material, and the current classification methods in my country are not uniform. In the "Technical Specifications for the Application of Fly Ash Concrete" (GBJ 146-90), fly ash is divided into three grades: I, II, and III from the indicators of fineness, ignition loss, water demand ratio, and sulfur trioxide content; Fly ash used in cement and concrete" (GB / T 1596-2005) divides fly ash into F and C according to coal types. F fly ash is collected from anthracite calcination, and C Fly ash is coal ash collected by calcining lignite or sub-bituminous coal, and its calcium oxide ...

Claims

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Application Information

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IPC IPC(8): C04B28/00C04B18/08
CPCY02W30/91
Inventor 杨文王军赵日煦孙克平吴静王艳王海亮
Owner CHINA STATE CONSTR READY MIXED CONCRETE CO LTD
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