Rapid Construction Technology for Railroad Concrete Infrastructure: Microwave Heat Curing Technology

2015 ◽  
Author(s):  
Taehoon Koh ◽  
Seonkeun Hwang ◽  
Junghoon Yoo ◽  
Donggeun Lee
Keyword(s):  
Heating System ◽  
Curing Temperature ◽  
Cold Weather ◽  
Concrete Lining ◽  
Construction Technology ◽  
Construction Process ◽  
Construction Period ◽  
Heat Curing ◽  
Rapid Construction ◽  
Microwave Heat

The cast-in-place concrete lining construction process represents about 25% of the total railroad tunnel construction period. Moreover, the construction period for lining concrete depends on the speed of the curing process of the lining concrete. Therefore, in cold weather when the air temperature in mountain railroad tunnel is consistently 10 degrees or below, equipment for heat insulation of cast-in-place concrete lining, such as a portable fossil fuel heater, must also be prepared to maintain an appropriate curing temperature in the tunnel. It generally takes about 24 to 36 hours to reach the compressive strength (3 to 5MPa) required to remove the lining form. Recently, microwave heat curing technology has been developed as a way of substantially reducing the concrete curing time, to achieve a reduction in the total construction period. The microwave heating system developed in this technology is comprised of a microwave generator, cavity, insulator, and exothermic body (microwave irradiated pyrogen). In this system, microwaves generated from the magnetron are irregularly reflected inside the cavity, and rapidly heat up the exothermic body so that the heat is transferred to the lining form and the concrete in turn, resulting in the accelerated hydration of concrete. Based on the field test data from the construction of the railroad tunnel cast-in-place concrete lining, it is found that this technology is able in 6 to 12 hours to complete the curing of concrete lining sufficiently to remove the form. It is hoped that this approach will substantially reduce the construction period and cost of tunnel lining, even during cold-weather.

Jacking Force Controlling Technique of PC Beam Flexible Piers Based on Multiple Points Pushing Method

2013 ◽  
Vol 395-396 ◽  
pp. 548-554
Author(s):  
Cheng Zhu ◽  
Rui Li ◽  
Zhi Yun Zhang
Keyword(s):  
Construction Cost ◽  
Construction Method ◽  
Control Technology ◽  
Construction Technology ◽  
Relative Navigation ◽  
Construction Process ◽  
Multiple Points ◽  
Construction Period ◽  
Jacking Force

With the advantages such as shortening the construction period, not affecting the relative navigation and effectively reducing the construction cost, jacking construction technology has been widely applied, as the construction method compared with other conventional construction method is more complicated, it is necessary to discuss the control technology of jacking force during the construction process.

scholarly journals Compressive Strength Gain Behavior and Prediction of Cement-Stabilized Macadam at Low Temperature Curing

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yongli Xu ◽  
Guang Yang ◽  
Hongyuan Zhao
Keyword(s):  
Compressive Strength ◽  
Low Temperature ◽  
Curing Temperature ◽  
Strength Development ◽  
Construction Process ◽  
Strength Gain ◽  
Estimation Model ◽  
Maturity Method ◽  
Temperature Ranges ◽  
Natural Temperature

For cement-based materials, the curing temperature determines the strength gain rate and the value of compressive strength. In this paper, the 5% cement-stabilized macadam mixture is used. Three indoor controlled temperature curing and one outdoor natural curing scenarios are designed and implemented to study the strength development scenario law of compressive strength, and they are standard temperature curing (20°C), constant low temperature curing (10°C), day interaction temperature curing (varying from 6°C to 16°C), and one outdoor natural temperature curing (in which the air temperature ranges from 4°C to 20°C). Finally, based on the maturity method, the maturity-strength estimation model is obtained by using and analyzing the data collected from the indoor tests. The model is proved with high accuracy based on the validated results obtained from the data of outdoor tests. This research provides technical support for the construction of cement-stabilized macadam in regions with low temperature, which is beneficial in the construction process and quality control.

Research on Detail-Structure Construction Technology of Outside Heat Preservation of Exterior Walls

2014 ◽  
Vol 548-549 ◽  
pp. 1790-1794
Author(s):  
Xia Zhao ◽  
You Ping Ding ◽  
Xiu Yan Zhang
Keyword(s):  
Construction Technology ◽  
Air Conditioner ◽  
Construction Process ◽  
External Wall ◽  
Similar Construction ◽  
Preservation Technology ◽  
Structure Treatment ◽  
Heat Preservation

In order to analyze the effect of heat preservation, the heat preservation technology of detail structure, such as decorative lines of external walls, edge beam and edge column, windows, balcony and laying position of air conditioner, have been well treated under the system of thin plastered external wall based on EPS. Moreover, the technical-economy benefits of detail structure treatments have been analyzed by comparing with those without detail structure treatment. The results show that better heat preservation and economy benefits would be created by detail structure treatment, which could provide good reference for similar construction process.

The Study on Foaming Characteristics of Foamed Asphalt in Cold Recycling Technology

2011 ◽  
Vol 243-249 ◽  
pp. 4293-4296
Author(s):  
Jing Li Liu ◽  
Lian Yu Wei ◽  
Guo Qiang Zhang
Keyword(s):  
Quality Control ◽  
Theoretical Basis ◽  
Asphalt Mixture ◽  
Construction Process ◽  
Environment Protection ◽  
Effect Evaluation ◽  
Construction Period ◽  
Foamed Asphalt ◽  
Recycling Technology ◽  
Cold Recycling

Through the foaming mechanism and foaming effect evaluation, this paper analyzes the production procedure, optimum content and strength of foamed asphalt mixture thoroughly. Combined with the construction process quality control and inspection and acceptance criteria, this paper provides data for reference and theoretical basis for application of cold recycled technology of foamed asphalt to pavement project. Its construction without disrupting traffic, thus shorten the construction period and improve efficiency, which also have advantages such as energy conservation, environment protection and economy. Above all, it is beneficial to foamed asphalt′s popularization and application.

scholarly journals “Integrated” Solution and Engineering Application of Assembled Cable-Stayed Pedestrian Landscape Overbridge

2019 ◽  
Vol 2 (3) ◽  
pp. 11
Author(s):  
Xinrui Shao
Keyword(s):  
Building Materials ◽  
Process Integration ◽  
Engineering Application ◽  
Construction Process ◽  
Construction Period ◽  
Surrounding Environment ◽  
The People ◽  
Modern Cities ◽  
Safety And Stability ◽  
Reducing Energy

The construction of modern cities emphasizes the nature and harmony among the “people”, “things” and “environment”, reflecting the harmony and unity of the formal beauty, functional beauty and surrounding environment of architecture. Based on the introduction of the design concept of the assembled pedestrian overbridge, through the Jianhua Building Materials Group’s frst “pre-fabricated low-rise tower-stayed pedestrian landscape overbridge” project in China, this paper proposes a solution that can improve the landscape design of the overbridge and reduce the construction complexity of the overbridge, the assembly product supply and the construction process “integration” under the premise of ensuring the safety and stability of the pedestrian overbridge, whose prefabricated production and assembly construction, shortening the construction period, reducing energy consumption, reducing pollution, and obtaining good social comprehensive benefts.

Research on the Construction Technology of High Brick Chimney

2011 ◽  
Vol 255-260 ◽  
pp. 65-69
Author(s):  
Hua Feng Deng ◽  
Min Zhu ◽  
Jing Guo ◽  
Tao Lu
Keyword(s):  
Detailed Calculation ◽  
Construction Technology ◽  
Structural Members ◽  
Construction Process ◽  
Horizontal Cross Section ◽  
Transport Equipment ◽  
Work Surface ◽  
The Stability ◽  
Calculation Analysis ◽  
Technical Measures

Chimney is the building which is high but the horizontal cross section is small, so the high altitude work surface is small and difficult to construct, in which the stability of the scaffold and the safety of vertical transport equipment are especially important. For the serious problems arising in the prophase construction of the 50m chimney, double rows steel pipe scaffold was designed outside the chimney, and the vertical transportation uses the external grillage hoisting frame. Reformed the internal existing scaffold into pedestrian passage to separate people and material, and a detailed calculation analysis of the structural members such as scaffold, grillage hoisting frame and other structures was carried out. Large deformation, destabilization and other safety problems of the scaffold, grillage hoisting frame and other structures were not arising during the anaphase construction process, which indicates that the construction technical measures and calculation and analysis results are with important guiding significance to guarantee the smooth of the construction, and also can be referenced by other similar projects.

Analysis of Crack Reason on Block No.0 of Continuous Rigid-Frame Bridge

2011 ◽  
Vol 71-78 ◽  
pp. 1392-1397 ◽  
Author(s):  
Wen Xiong Huang ◽  
Li Ying Tan ◽  
Kang Jing Zhou
Keyword(s):  
Temperature Difference ◽  
Construction Technology ◽  
Actual Situation ◽  
Construction Process ◽  
The Real ◽  
Continuous Rigid Frame Bridge ◽  
Rigid Frame ◽  
Technology Process ◽  
Rigid Frame Bridge ◽  
Distribution Of Stress

Cracks on the Joint Part between Pier and Girder, namely Block NO.0 in the construction process, has become one of the major diseases of continuous rigid-frame bridges. Based on the real construction technology, process and environment of Yuquanxi Bridge, the uneven distribution of stress caused by various factors is precisely analyzed by ANSYS. The shrinkage difference of concrete, the excessive hydration heat, and the sunshine temperature difference is accurately simulated respectively. By comparing the numerical results with actual cracks condition, the results prove that the theoretical analyse is accord with the actual situation, and the real reason of cracks on Block No.0 of Yuquanxi Bridge is uncovered. This study is of great practical value in preventing cracks and improving bridge construction technology.

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