Control method for crack of large-volume concrete of arch support foundation of large-span stiff framework arch bridge
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A stiff skeleton and control method technology, applied in arch bridges, infrastructure engineering, bridges, etc., can solve problems such as shrinkage cracking, and achieve the effects of small shrinkage deformation, reduced risk of cracking, and low adiabatic temperature rise
Inactive Publication Date: 2021-03-23
GUANGXI ROAD & BRIDGE ENG GRP CO LTD
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[0008] Aiming at the problem in the prior art that the concrete of the abutment foundation of a long-span stiff skeleton arch bridge is prone to shrinkage and cracking during the construction period, the present invention provides a method for controlling cracks in the large-volume concrete of the abutment foundation of a long-span stiff skeleton arch bridge. Design, optimization of concrete raw materials, design and optimization of low-temperature-rising crack-resistant concrete mix ratio, pouring and vibration, and moisture-retaining and maintenance technology form a complete set of technical solutions, which can effectively control factors such as temperature, self-shrinkage, and drying shrinkage of the abutment foundation concrete. cause shrinkage cracks
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Embodiment 1
[0055] The method for controlling large-volume concrete cracks in the abutment foundation of a long-span stiff skeleton arch bridge includes the following measures, which are implemented in sequence according to the construction steps:
[0056] 1) According to the environment of the abutment foundation concrete, the total volume of pouring and the different construction seasons, the maximum layered pouring thickness of the abutment foundation concrete in summer is determined to be ≤ 4m;
[0057] 2) Determine the low-temperature-rise anti-cracking concrete raw materials and their storage methods;
[0058] The raw material of the low-temperature rising anti-cracking concrete is selected from cement, fly ash, granulated blast furnace slag powder, fine aggregate, coarse aggregate, water reducing agent and anti-cracking agent;
[0059] Cement, selected from P.O42.5 grade ordinary Portland cement, whose specific surface area is ≤350m 2 / kg, alkali content ≤0.6%, C 3 A content≤8.0%...
Embodiment 2
[0083] The difference between the large-span rigid skeleton arch bridge abutment foundation mass concrete crack control method and embodiment 1 is:
[0084] Step 2) the anti-cracking agent is made up of the following components by weight percentage:
[0085]
[0086]
[0087] In step 3), the water-binder ratio of the low-temperature rise crack-resistant concrete is 0.42, and the water consumption is 160kg / m 2 , low temperature rising cracking concrete sand rate 45%, other with embodiment 1.
Embodiment 3
[0089] The difference between the large-span rigid skeleton arch bridge abutment foundation mass concrete crack control method and embodiment 1 is:
[0090] Step 2) the anti-cracking agent is made up of the following components by weight percentage:
[0091]
[0092] In step 3), the water-binder ratio of the low-temperature rise crack-resistant concrete is 0.43, and the water consumption is 155kg / m 2 , low temperature rising cracking concrete sand rate 44%, other with embodiment 1.
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Abstract
The invention discloses a control method for a crack of large-volume concrete of an arch support foundation of a large-span stiff framework arch bridge. The method comprises the following measures sequentially implemented according to construction steps of 1) determining that the maximum layered pouring thickness of the concrete of the arch support foundation is less than or equal to 4 m accordingto the environment of the concrete of the arch support foundation, the total pouring volume and the different construction seasons; 2) determining a low-temperature-rise anti-crack concrete raw material and a storage mode thereof; 3) determining the mix proportion of the low-temperature-rise anti-crack concrete; 4) transporting and vibrating the concrete; and 5) determining a heat preservation and moisture preservation maintenance process. The control method for the crack of the large-volume concrete of the arch support foundation of the large-span stiff framework arch bridge has the advantages that operation and implementation are easy, the concrete cracking risk in the construction period of the arch support foundation can be remarkably reduced, the safety and durability of an arch support foundation structure are improved, safe, stable and continuous use is guaranteed, and remarkable social and economic benefits are achieved.
Description
【Technical field】 [0001] The invention belongs to the technical field of road and bridge construction engineering, and relates to a method for controlling large-volume concrete cracks in the abutment foundation of a large-span rigid skeleton arch bridge. 【Background technique】 [0002] In recent years, the long-span rigid frame arch bridge has developed rapidly due to its beautiful shape and unique mechanical properties, and has achieved fruitful results in theoretical research, structural innovation and construction technology. With the continuous breakthrough of the span of stiffened frame arch bridges, the quality control of shrinkage cracks during the construction period of mass concrete in abutment foundations has been paid more and more attention. However, according to public information, there are different degrees of shrinkage cracks in the large-volume concrete of the abutment foundation during the construction period. risks and cause adverse social impacts. [00...
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