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Carbon dioxide-maintained recycled aggregate concrete and manufacturing method thereof

A recycled aggregate and carbon dioxide technology, applied in the field of concrete, can solve the problems of elastic modulus decrease, compressive strength increase, high water absorption rate, etc., and achieve the effect of increased water absorption rate, mechanical properties and durability improvement

Inactive Publication Date: 2017-02-22
吉林省圣翔建材集团有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Compared with natural stone aggregate, recycled aggregate has the following disadvantages: high water absorption, low crushing index, high void ratio
Therefore, when the recycled aggregate is used to make concrete, it will bring the weaknesses of concrete slump, low strength, decreased elastic modulus, high drying shrinkage and creep, and decreased durability, which will lead to the degradation of recycled aggregate. Very limited use in structural concrete
[0006] Studies have shown that the compactness of concrete increases after carbonization, thereby increasing its compressive strength. However, for reinforced concrete, the steel bars in the concrete are easy to rust due to the reduction of its pH value after carbonization. The method of carbonation curing is used to improve recycled aggregates. The performance does not need to worry about the problem of steel modification

Method used

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  • Carbon dioxide-maintained recycled aggregate concrete and manufacturing method thereof
  • Carbon dioxide-maintained recycled aggregate concrete and manufacturing method thereof
  • Carbon dioxide-maintained recycled aggregate concrete and manufacturing method thereof

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Experimental program
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Effect test

Embodiment 1

[0018] Table 1 lists the recycled aggregates with a particle size of 20 mm and 10 mm (the water absorption before treatment was 6.85% and 7.92%, and the specific gravity was 2386 kg / m3 and 2348 kg / m3) using different concentrations of Physical properties and mechanical properties of recycled aggregates measured according to standard methods after carbon dioxide treatment under different pressures and different curing times.

[0019] From the data listed in Table 1, it can be seen that with the CO 2 As the concentration increases, the pressure in the curing room increases and the treatment time increases, the specific gravity and compression index of the recycled aggregate after treatment increase, and the water absorption decreases. CO 2 When the concentration reaches 100%, the pressure is 2.0Ba and the curing time is 72 hours, the effect of improving aggregate performance is the best. But when the pressure exceeds 2.0 and the curing time exceeds 48 hours, the change of aggr...

Embodiment 2

[0023] Table 2 lists the proportions of the concrete produced by using the recycled aggregates with a concentration of 100% carbon dioxide and a pressure of 2.0Ba for 48 hours, and Table 3 lists the mechanical properties of the concrete produced according to the proportions in Table 2. performance and durability. It can be seen from Table 3 that the mechanical properties and durability of concrete using untreated recycled aggregates (R0-50 and R0-100) are poor. Also, the performance of concrete decreases with the increase of recycled aggregate.

[0024] Utilizes CO compared to concrete made from untreated recycled aggregates 2 The 28-day compressive strength, splitting strength and elastic modulus of the treated concrete are greatly improved, the 112-day shrinkage rate is reduced, and the 365-day creep is reduced. 50% recycled aggregate replaces natural aggregate to make concrete whose performance fully meets the requirements of structural concrete.

[0025] Table 2 – Pro...

Embodiment 3

[0030] Table 4 lists the proportions of recycled aggregates cured for 48 hours under the condition of 100% carbon dioxide at a pressure of 2.0Ba under different cement contents, different water-cement ratios, and different mineral additive contents. It is the performance of the concrete manufactured according to the ratio in Table 4. It can be seen from Table 5 that the mechanical properties and durability of recycled aggregate concrete can be greatly improved by increasing the cement content, reducing the water-cement ratio, and adding mineral additives such as kaolin powder or silica fume, while adding fly ash will reduce Concrete 28-day strength, but durability of concrete can be improved.

[0031] Table 4 – Proportions of recycled aggregate concrete with different cement contents and different water-cement ratios

[0032]

[0033] Table 5 – Properties of recycled aggregate concrete with different cement contents and different water-cement ratios

[0034]

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Abstract

The invention discloses a method for improving the physical property and the mechanical property of a recycled aggregate by a carbon dioxide (CO2) maintaining method, which is suitable for recycled aggregate concrete and high-performance recycled aggregate concrete. The invention also provides a manufacturing method of the recycled aggregate structure concrete. The manufacturing method of the concrete comprises the steps: putting the recycled aggregate into a maintaining box capable of bearing a certain pressure, and introducing CO2 gas and maintaining for a certain time so as to reduce the water absorption rate of the recycled aggregate and increase the crush index of the recycled aggregate, wherein the used CO2 is tail gas discharged by thermal power or cement production; and uniformly stirring cement, the maintained recycled aggregate, sand or gravel or fine recycled aggregate and other mineral additive according to a certain mixing proportion, conveying or pumping the materials to a construction site and pouring to obtain the recycled aggregate structure concrete manufactured by the method and a concrete structure.

Description

technical field [0001] The invention belongs to the concrete category in the field of building materials, and relates to a structural concrete manufactured by using a carbon dioxide curing method to improve the physical and mechanical properties of recycled aggregates, and a manufacturing method of the structural concrete. Background technique [0002] With the rapid development of the economy, in many large cities in China, the waste generated by the construction industry has also become a public hazard. These wastes not only cause serious damage to the environment, but are also competing with human beings for living space, which seriously affects the sustainable development of the country. Therefore, it is imminent to develop new technologies to reduce, recycle and utilize construction waste. [0003] Construction waste is mainly produced during the demolition of old buildings and the construction of new buildings. Therefore, to reduce buildings, it is necessary to adop...

Claims

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Application Information

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IPC IPC(8): C04B40/02C04B28/04C04B28/06C04B14/02C04B14/06C04B18/08
CPCY02W30/91
Inventor 寇世聪明臣
Owner 吉林省圣翔建材集团有限公司
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