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Application of mud-resistant slump-retaining type water reducing agent to building solid waste recycled aggregate concrete

A technology of recycled concrete and recycled aggregate, applied in the field of concrete, can solve the problems of high shrinkage rate, low dispersibility and slump retention of polycarboxylate superplasticizer, and high water demand, and achieves improved fluidity and cohesion, The effect of shortening the mold turnover cycle and accelerating the hydration reaction rate

Active Publication Date: 2018-07-20
SHANGHAI CONSTR BUILDING MATERIALS TECH GRP CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] 1. High water demand and high admixture content;
[0015] 2. Large loss of slump over time
[0016] 3. Large shrinkage rate
However, in practical application, it is found that the traditional polycarboxylate superplasticizer is very sensitive to the mud content in the aggregate. With the increase of the mud content in the aggregate, the dispersibility and slump retention of the polycarboxylate superplasticizer are obvious. Reduce, or even lose dispersion, in the environment where high-quality sand and gravel resources are increasingly scarce and almost exhausted, and under the background of environmental protection and sustainable development of concrete, the application of recycled aggregates and the implementation and promotion of recycled aggregate concrete have great potential must do
To realize the application and popularization of recycled concrete, the technical difficulties that urgently need to be solved are the problems of poor workability and large loss over time due to the high mud and powder content of recycled aggregates. Slump agent, is an urgent problem to be solved

Method used

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  • Application of mud-resistant slump-retaining type water reducing agent to building solid waste recycled aggregate concrete
  • Application of mud-resistant slump-retaining type water reducing agent to building solid waste recycled aggregate concrete
  • Application of mud-resistant slump-retaining type water reducing agent to building solid waste recycled aggregate concrete

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] An embodiment of the mud-resistant and slump-preserving water-reducer of the present invention, the mud-resistant and slump-preserving water-reducer described in this embodiment is prepared by the following method:

[0050] In a 500ml four-necked glass flask equipped with a stirrer, a thermometer, and a reflux condenser, add metered 50wt% PEI aqueous solution and phosphorous acid H 3 PO 3 ,, 0.3 milliliters of 37wt% concentrated hydrochloric acid (volume accounted for 0.1% of the total reaction system), fully stirred, heated to 40 ° C, slowly added dropwise metered 37% formaldehyde solution, after 2 hours, slowly heated to 80 ° C, Continue to react for 3 hours, the solution is yellow-brown, reduce the temperature to below 40°C, add 40% sodium hydroxide solution, adjust the pH=8-9, and obtain the product sodium polyethyleneimine phosphite.

[0051] Among them, PEI: H 3 PO 3 : The molar ratio of HCHO is 1.0:0.2:0.9.

[0052] The PEI structure of this embodiment is a l...

Embodiment 2

[0057] As an embodiment of the present invention, the mud-resistant and slump-retaining water reducer described in this embodiment is prepared by the following method:

[0058] In a 500ml four-necked glass flask equipped with a stirrer, a thermometer, and a reflux condenser, add metered 50wt% PEI aqueous solution and phosphorous acid H 3 PO 3 , 0.25 milliliters of 37wt% concentrated hydrochloric acid (volume accounts for 0.08% of the total reaction system), fully stirred, heated up to 45 ° C, slowly added dropwise metered 37% aqueous formaldehyde solution, and after 2.5 hours, the dropwise addition was completed, slowly heated to 85 ° C, continued React for 2 hours, the solution is yellow-brown, reduce the temperature to below 40°C, add 40% sodium hydroxide solution, adjust the pH=8-9, and obtain the product polyethyleneimine sodium phosphite.

[0059] Among them, PEI: H 3 PO 3 : The molar ratio of HCHO is 1.0:1.5:0.2.

[0060] The PEI structure of this embodiment is diffe...

Embodiment 3

[0067] As an embodiment of the present invention, the mud-resistant and slump-retaining water reducer described in this embodiment is prepared by the following method:

[0068] In a 500ml four-necked glass flask equipped with a stirrer, a thermometer, and a reflux condenser, add metered 50wt% PEI aqueous solution and phosphorous acid H 3 PO 3 , 0.3 milliliters of 37wt% concentrated hydrochloric acid (volume accounts for 0.1% of the total reaction system), fully stirred, heated up to 43 ° C, slowly added dropwise metered 37% formaldehyde solution, and the dropwise addition was completed in 3 hours, slowly heated up to 90 ° C, continued React for 3 hours, the solution is yellow-brown, reduce the temperature to below 40°C, add 40% sodium hydroxide solution, adjust the pH=8-9, and obtain the product sodium polyethyleneimine phosphite.

[0069] Among them, PEI: H 3 PO 3 : The molar ratio of HCHO is 1.0:2.2:2.1.

[0070] The PEI structure of the present embodiment is branched PE...

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Abstract

The invention discloses an application of a mud-resistant slump-retaining type water reducing agent to building solid waste recycled aggregate concrete and further discloses the building solid waste recycled aggregate concrete containing the mud-resistant slump-retaining type water reducing agent. On the basis of the principle of polymer structure design, a water-soluble polymer PEI (polyethyleneimine) is modified through a Mannich reaction, phosphorous acid functional groups are introduced, and the slump-retaining type water reducing agent with special tolerance to mud and recycled aggregatepowder is synthesized. The molecular structure of the product contains a large amount of amino with positive charges and is in a cluster shape, the cluster structure is physically cross-linked, a complexing adsorption layer is formed on the surface of cement particles, excellent slump-retaining capacity is obtained, and defects of poor dispersity and low water-reducing rate of a slump-retaining type polycarboxylate superplasticizer in the market are overcome; the mud-resistant slump-retaining type water reducing agent is used independently or compounded with other functional polycarboxylate superplasticizers for use and has good water reducing and slump retaining performance for the building solid waste recycled aggregate concrete.

Description

technical field [0001] The invention relates to the technical field of concrete, in particular to the application of a mud-resistant and slump-preserving water reducer in construction solid waste recycled aggregate concrete. Background technique [0002] Concrete is the second most consuming material on earth after water. The annual consumption in the world exceeds 20 billion tons. While the consumption of concrete is huge, it also causes social and environmental problems of resource consumption and waste disposal. [0003] my country is the country with the largest number of newly built buildings in the world, and it is also the country with the largest number of old buildings demolished every year in the world. According to preliminary estimates, the demolition of buildings per square meter will generate about 1 ton of construction solid waste. The rapid development of cities will inevitably produce a large amount of construction solid waste, and proper disposal of constru...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G73/02C04B24/28C04B103/30
CPCC04B24/243C04B2103/302C08G73/0206
Inventor 张小富吴德龙冯波赵利华
Owner SHANGHAI CONSTR BUILDING MATERIALS TECH GRP CO LTD
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