Concrete admixture for inhibiting alkali reactivity of metamorphic rock aggregate and preparation method and application of concrete admixture

A concrete admixture and metamorphic rock technology, which is applied in the field of long-term concrete durability technology and building materials, can solve the problems of concrete durability decline and concrete loss of use value, and achieve the effects of reduced transportation, significant inhibition effect, and significant inhibition effect

Inactive Publication Date: 2013-05-01
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the alkali-aggregate reaction generally occurs gradually after a few years after the concrete is formed, the durability of the concrete is reduced as a result, and in severe cases, the concrete loses its use value.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Prepare a kind of concrete admixture used in C25 metamorphic rock aggregate machine-made sand concrete for bridges, subgrades, tunnels, and culverts in a certain project to inhibit the alkali activity of metamorphic rock aggregates. The ingredients are as follows:

[0037] Secondary fly ash 97.972wt%;

[0038] LiOH 0.160wt%;

[0039] Silane powder 0.911wt%;

[0040] Sodium lignosulfonate 0.957wt%;

[0041] The preparation process of the admixture is as follows: after weighing the components according to the proportion, pour the weighed components into the mixer, add the silane at the end, and stir for 5-10 minutes until they are evenly mixed.

[0042] The amount of the admixture in the concrete is 43wt% of the cement weight; the concrete is tested using the American Society for Testing and Materials standard (ASTM C1260 standard), and the expansion rate of the 14d mortar bar is 0.067%, which is higher than that of the benchmark test. Parts (no admixture added) expans...

Embodiment 2

[0044] Prepare a kind of concrete admixture used in C30 metamorphic rock aggregate machine-made sand concrete for bridges, subgrades, tunnels, and culverts in a certain project to inhibit the alkali activity of metamorphic rock aggregates. The ingredients are as follows:

[0045] Secondary fly ash 97.611wt%;

[0046] Li 2 CO 3 0.518wt%;

[0047] Silane emulsion 1.816wt%;

[0048] Rosin soap air-entraining agent 0.055wt%.

[0049] The preparation process of the admixture is the same as in Example 1.

[0050] The amount of the admixture in the concrete is 21.5wt% of the cement weight; the concrete is tested using the American Society for Testing and Materials standard (ASTM C1260 standard), and the expansion rate of the 14d mortar bar is 0.070%, which is higher than that of the benchmark The expansion rate of the test piece (no admixture added) was reduced by 77.5%.

Embodiment 3

[0052] Prepare a kind of concrete admixture used in C30 metamorphic rock aggregate machine-made sand concrete for bridges, subgrades, tunnels, and culverts in a certain project to inhibit the alkali activity of metamorphic rock aggregates. The ingredients are as follows:

[0053] Primary fly ash 98.586wt%;

[0054] Li 2 CO 3 0.233wt%;

[0055] Silane powder 1.149wt%;

[0056] Sodium Lauryl Sulfate 0.032wt%.

[0057] The preparation process of the admixture is the same as in Example 1.

[0058] The amount of the admixture in the concrete is 42.9wt% of the cement weight; the concrete is tested using the American Society for Testing and Materials standard (ASTM C1260 standard), and the expansion rate of the 14d mortar bar is 0.081%, which is higher than that of the benchmark The expansion rate of the specimen (without additives) was reduced by 79.8%.

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Abstract

The invention relates to a concrete admixture for inhibiting the alkali reactivity of a metamorphic rock aggregate. The concrete admixture comprises the following components in percent by weight of 94-99 wt percent of mineral admixtures, 0.1-1.5wt percent of lithium compound, 0.5-3 wt percent of silane and 0.02-4wt percent of air entraining agent. A preparation method of the concrete admixture comprises the steps of: weighing all components according to the proportion, pouring the weighed components in a stirrer, adding the silane, and stirring for 5-10min until uniformly mixing to obtain the concrete admixture. The concrete admixture for inhibiting the alkali reactivity of the metamorphic rock aggregate can be used for preparing metamorphic rock machine-made sand concrete with different strength grades and applications, and is relatively remarkable in inhibition effect of the metamorphic rock concrete alkali aggregate.

Description

technical field [0001] The invention relates to a concrete admixture for inhibiting alkali activity of metamorphic rock aggregate, a preparation method and application thereof, and belongs to the field of long-term durability technology of concrete in traffic, bridge and road engineering and building materials. Background technique [0002] Alkali-aggregate reaction refers to the occurrence between certain alkali-active mineral components in concrete aggregates (sand, stone) and soluble alkaline solutions (mainly KOH and NaOH) from cement and admixtures in the pores of concrete. These alkaline solutions may come from such reactions that cause concrete volume expansion and even cracking, change the microstructure of concrete, significantly reduce the mechanical properties of concrete such as compressive strength, flexural strength, and elastic modulus, and seriously affect the structure. safe use. Because the alkali-aggregate reaction generally occurs gradually after several...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B24/42
Inventor 蒋正武韩超田曼丽
Owner TONGJI UNIV
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