The Hydration Heat Analysis for Sealing Concrete of Swivel Construction Open Thin Wall Arch

2012 ◽  
Vol 253-255 ◽  
pp. 440-444
Author(s):  
Xiong Hui Feng ◽  
Zi Qiang Zhu ◽  
Zhi Yong Li ◽  
Xin Wu
Keyword(s):  
Simulation Model ◽  
Heat Effect ◽  
Hydration Heat ◽  
Thin Wall ◽  
Arch Bridge ◽  
Boundary Constraint ◽  
Constant Coefficients ◽  
Complex Boundary ◽  
Concrete Hydration ◽  
Simulation Parameters

The sealing concrete of arch bridge will be constructed after swivel construction of it finished. The concrete has such characteristics like huge size, smaller heat radiating area and more complex boundary constraint. According to the cracking situation of this type bridges in recent years, the paper established hydration heat simulation model of it using MIDAS2010 program and numerical analyzed for the model. The hydration heat constant coefficients and placing temperature of the concrete hydration heat effect have been analyzed by simulation parameters base on that. And the results showed that it is an important reason causing the cracking of the concrete.

Analysis of Model Test Data for CFG Group Piles in Permafrost Areas

2014 ◽  
Vol 501-504 ◽  
pp. 16-19
Author(s):  
Zhao Jian Luan ◽  
Qiang Xin ◽  
Yan Min Jia
Keyword(s):  
Temperature Field ◽  
Heat Effect ◽  
Frozen Soil ◽  
Hydration Heat ◽  
Measured Temperature ◽  
Geological Conditions ◽  
Soil Temperatures ◽  
Concrete Hydration ◽  
Group Piles ◽  
Model Temperature

In this paper, the author simulates geological conditions of permafrost areas, establi-shes CFG group piles indoor model, observes the pile and frozen soil temperature field, then compares the calculated results of the group piles and frozen soil temperatures under concrete hydration heat effect by using ABAQUS with the measured temperature data, thus determines the applicability of ABAQUS for analysis of CFG group piles temperature in permafrost areas, in order to analyze temperature distribution regularities of group piles and frozen soil under concrete hydration heat effect, thermal perturbation range of CFG group piles in permafrost areas, and effects of different concrete molding temperature on model temperature field.

Embedded piezoelectric transducers based early-age hydration monitoring of cement concrete added with accelerator/retarder admixtures

2020 ◽  
pp. 1045389X2096991 ◽  
Author(s):  
Demi Ai ◽  
Chengxing Lin ◽  
Hongping Zhu
Keyword(s):  
Heat Effect ◽  
Hydration Heat ◽  
Strength Development ◽  
Early Age ◽  
Strength Gain ◽  
Element Analysis ◽  
Electromechanical Impedance ◽  
Hardening Process ◽  
Concrete Hydration ◽  
Early Age Hydration

Accelerator/retarder admixtures are often added into concrete to improve its early-age strength, which needs to be effectively monitored during its hardening process. The electromechanical impedance (EMI) technique has validated its effectiveness for concrete hydration monitoring, this study attempted to extend the EMI technique to monitor 28-day age of strength gain in concrete that added with accelerator/retarder admixtures. Two types of new piezoelectric (PZT) transducers namely cement/aluminum embedded PZT (CEP/AEP) were proposed for EMI monitoring. The feasibility of the CEP and AEP was first verified via finite element analysis, where hydration heat effect on the two types of transducers was comparatively evaluated by numerical modeling. In the experiment, CEP/AEP transducers were applied to monitor the strength gain in concrete cubes, where characteristics of EMI signature and its statistical indices including root mean square deviation (RMSD) and mean absolute percentage deviation (MAPD) were analyzed and correlated to strength development in concrete. Monitoring results demonstrated that concrete hydration triggered by retarder/accelerator were successfully captured by EMI signature. RMSD and MAPD indices further indicated that AEP had preferable performance than CEP transducer for monitoring early-age strength gain of concrete, as it could immune from hydration heat effect.

Sensitivity Analysis and Selection of Check Index of Signal Intersection Simulation Model Based on VISSIM

2019 ◽  
Vol 2 (5) ◽  
Author(s):  
Mengda Zhang ◽  
Chenjing Zhou ◽  
Tian-tian Zhang ◽  
Yan Han
Keyword(s):  
Sensitivity Analysis ◽  
Simulation Model ◽  
Optimal Process ◽  
Parameter Calibration ◽  
Index Set ◽  
The Core ◽  
Core Module ◽  
Simulation Parameter ◽  
Simulation Parameters ◽  
Selection Of

Selecting check index quantitatively is the core of the calibration of micro traffic simulation parameters at signal intersection. Five indexes in the node (intersection) module of VISSIM were selected as the check index set. Twelve simulation parameters in the core module were selected as the simulation parameters set. Optimal process of parameter calibration was proposed and model of the intersection of Huangcun west street and Xinghua street in Beijing was built in VISSIM to verify it. The sensitivity analysis between each check index and simulation parameter in their own set was conducted respectively. Sensitive parameter sets of different check indices were obtained and compared. The results show that different indexes have different size of set, and average vehicle delay's is maximum, so it's necessary to select index quantitatively. The results can provide references for scientific selection of the check indexes and improve the study efficiency of parameter calibration.

Study on Dynamic Properties of the Intake Tower with Finite Element Method

2014 ◽  
Vol 501-504 ◽  
pp. 1888-1891 ◽  
Author(s):  
Cheng Lin Gong ◽  
Hua Liu ◽  
Jian Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Properties ◽  
Complex Structure ◽  
Hollow Structure ◽  
Complex Loading ◽  
Thin Wall ◽  
Finite Element Software ◽  
Complex Boundary ◽  
Tower Foundation

Intake tower is a complex structure, which has complex boundary conditions and has complex loading situation. Intake tower is made up of reinforced concrete ,which is thin-wall hollow structure. It builds in the near the shore in the reservoir, its top bridge connects to the banks of the river, The tower is in the water and is under pressure, intake towers safety is very important under the action of earthquake. Based on the large finite element software ANSYS, the dynamic properties of the intake tower is studied, and the intake tower+ foundation is also studied. The research conclusions can be used as reference for engineering design.

Possibilities of Regulation of Temperature in Concrete during Hydration by Means of Selection of Suitable Input Materials

2014 ◽  
Vol 507 ◽  
pp. 199-203 ◽  
Author(s):  
Rudolf Hela ◽  
Jiri Zach ◽  
Martin Sedlmajer
Keyword(s):  
Blast Furnace ◽  
Portland Cement ◽  
Blast Furnace Slag ◽  
Hydration Heat ◽  
Concrete Hydration ◽  
Furnace Slag ◽  
Selection Of

Paper is focused on development of hydration heat in concrete in time. Possible ways of reduction of temperature during concrete hydration are mentioned. Paper presents study of possibilities of regulation temperature in concrete during hydration by selection of suitable input components. Blast furnace slag and micronized limestone were added to pure Portland cement; several variants of proportions were proposed.

Experimental Study on Temperature Fields of Dumbbell-Shape Section of CFST Arch Rib and its Effects

2010 ◽  
Vol 163-167 ◽  
pp. 2564-2570
Author(s):  
Bin Yang ◽  
Jin Hua Huang ◽  
Chun Jiao Lin ◽  
Xing Kun Wen ◽  
Mao Jun Liu
Keyword(s):  
Temperature Field ◽  
Temperature Effect ◽  
Time History ◽  
Steel Tube ◽  
Hydration Heat ◽  
Temperature Fields ◽  
Molding Process ◽  
Single Wave ◽  
Arch Bridge ◽  
The Impact

Based on the investigation of a constructing dumbbell-shaped concrete-filled steel arch bridge in Nanning, Guangxi, continuous on-site experimental researches on temperature field and its effects were carried out under the influence of hydration heat of concrete in the molding process of concrete-filled dumb-bell steel tubular arch bridge. On the basis of measured data, analysis on time-history law of temperature field and its effect under the impact of hydration heat of concrete of composite structure of concrete-filled steel tubes is made. The results reveal that temperature variation of hydration heat of the concrete within the steel tube is showed as follows: “Temperature up-continuous high temperature-temperature down-balance”. The structural temperature field, generated under the effect of hydration hea in the process of molding arch rib, is nonlinear temperature field. Concrete hydration temperature effect of crown section basically changes with temperature field simultaneously, while the residual strain of arch foot section is relatively large; hydration temperature effect of L/4 Section emerges peak fluctuations in concrete pouring process and finally levels off. Hydration temperature field of concrete has a great effect on crown section, which makes the steel tube continuously withstand the tension and compression alternatively, while the influence on the arch foot steel tube is not obvious. Surface strains of L/8, L/4, 3L/8 sections of steel tube transit from single-wave peak to dual-wave peak and finally turn into a single wave peak.

Temperature Effect of Concrete Hydration Heat under Atmospheric Wind Based on Fluid-Solid Coupling

2021 ◽  
Author(s):  
Moyan Zhang ◽  
Hong Xiao ◽  
Meng Wang ◽  
Mahantesh M. Nadakatti ◽  
Peng Chen
Keyword(s):  
Temperature Effect ◽  
Hydration Heat ◽  
Concrete Hydration

scholarly journals Dynamic Study of Thin Wall Part Turning

2011 ◽  
Vol 223 ◽  
pp. 591-599 ◽  
Author(s):  
Philippe Lorong ◽  
Arnaud Larue ◽  
Alexis Perez Duarte
Keyword(s):  
Cutting Speed ◽  
Machining Process ◽  
Thin Wall ◽  
Planning Stage ◽  
Cutting Test ◽  
Process Reliability ◽  
Key Factor ◽  
Simulation Parameters ◽  
And Control ◽  
Thin Wall Part

The numerical simulation of machining process is a key factor in the control of parts machining process. Its development aims at improving the process reliability and reduces the time spent during the process planning stage. In this context, we use a specific time domain simulation allowing modeling the dynamics of a thin wall part turning operation. After having introduced the basics of the proposed approach we present a specific cutting test that has been designed to specifically measure and control the dynamics of the part and the cutting conditions of a finishing toolpath. The influences of the cutting speed and damping coefficient on the chatter occurrence are discussed. In order to better control the simulation uses, an analysis of the simulation parameters influences on the simulated results is proposed.

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