Early Age Cracking Control in Semimassive Walls of RC Tanks by Internal Cooling

2021 ◽  
Vol 35 (4) ◽  
Author(s):  
Mariusz Zych ◽  
Trong-Chuc Nguyen
Keyword(s):  
Early Age ◽  
Internal Cooling ◽  
Cracking Control

Experimental Research on Hydration Heat Temperature of Concrete Box Girder in Low-Temperature Environment

2013 ◽  
Vol 470 ◽  
pp. 1045-1050
Author(s):  
Wei Gang Sun ◽  
Lai Jun Liu ◽  
Qun Hu Wu ◽  
Jian Ping Feng
Keyword(s):  
Low Temperature ◽  
Cross Section ◽  
Hydration Heat ◽  
Early Age ◽  
Box Girder ◽  
Heat Temperature ◽  
Cracking Control ◽  
Concrete Temperature ◽  
Temperature Environment ◽  
Concrete Box Girder

The temperature stress is one of the main reasons for early age cracking of concrete under low temperatures,it has the actual value of reference for the design and construction of concrete structures to study the regularities of hydration heat temperature of concrete box girder in low-temperature environment. Therefore, through the test of concrete box girder hydration heat temperature, this paper analyses the temp-time curves of temperature of the concrete box-bridge cross section. The results can be used for concrete temperature control and/or cracking control of box girder in similar environmental area.

Study on Cracking Control of High Performance Concrete at early Age

2013 ◽  
Vol 641-642 ◽  
pp. 504-507
Author(s):  
Ya Jun Wang ◽  
Jian Jun Wang ◽  
Chang Ying Guo ◽  
Meng Xing Cao
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Fine Powder ◽  
Test Methods ◽  
Early Age ◽  
Ratio Test ◽  
Mixture Ratio ◽  
Cracking Control ◽  
Binder Ratio ◽  
The Right

It analyzed the reasons for the early cracks in high-performance concrete, and prepared overall program to improve the mechanical properties and the durability of the HPC. It studied on cracking control of HPC at early age and improvement of impermeability by mixing ratio test. The result showed that , it get better inhibition on the early cracks by reasonable adjustment to the water-binder ratio, fly ash and mineral fine powder dosage with saturated aggregates and the right amount of expansion agent, and it also provided high-performance concrete for different performance with a mixture ratio test methods.

Cracking Control for Diaphragm of Long-Span Prestressed Concrete Box Girder Bridge at the Early Age

2013 ◽  
Vol 574 ◽  
pp. 1-9
Author(s):  
Guo Dong Li ◽  
Zong Lin Wang
Keyword(s):  
Prestressed Concrete ◽  
Diffusion Theory ◽  
Three Dimensional ◽  
Early Age ◽  
Control Techniques ◽  
Long Span ◽  
Prestressing Force ◽  
Cracking Control ◽  
Girder Bridge ◽  
Temperature Conduction

This paper presents the results of a study on the early-age cracking behavior of diaphragm in long-span prestressed concrete box girder bridge with cracking control techniques. Based on the three-dimensional hydration heat temperature conduction and humidity diffusion theory, and according to the similarity of differential equation between the humidity diffusion theory and temperature conduction theory, the early-age cracking of diaphragm was simulated by a three-dimensional finite element model with consideration of concrete shrinkage, creep, cement hydration heat and variation of temperature. The numerical simulation accurately predicts the cracking region and size and stress time history of diaphragm, and provides load standard for cracking control techniques of prestressing force. The cracking control techniques of prestressing force effectively avoid the early-age cracking of diaphragm by application of practical engineering.

scholarly journals Nondestructive Wireless Monitoring of Early-Age Concrete Strength Gain Using an Innovative Electromechanical Impedance Sensing System

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
C. P. Providakis ◽  
E. V. Liarakos ◽  
E. Kampianakis
Keyword(s):  
Concrete Strength ◽  
Strength Development ◽  
Early Age ◽  
Strength Gain ◽  
Impedance Sensing ◽  
Electromechanical Impedance ◽  
Sensing System ◽  
Cracking Control ◽  
Wireless Usb ◽  
Early Age Concrete

Monitoring the concrete early-age strength gain at any arbitrary time from a few minutes to a few hours after mixing is crucial for operations such as removal of frameworks, prestress, or cracking control. This paper presents the development and evaluation of a potential active wireless USB sensing tool that consists of a miniaturized electromechanical impedance measuring chip and a reusable piezoelectric transducer appropriately installed in a Teflon-based enclosure to monitor the concrete strength development at early ages and initial hydration states. In this study, the changes of the measured electromechanical impedance signatures as obtained by using the proposed sensing system during the whole early-age concrete hydration process are experimentally investigated. It is found that the proposed electromechanical impedance (EMI) sensing system associated with a properly defined statistical index which evaluates the rate of concrete strength development is very sensitive to the strength gain of concrete structures from their earliest stages.

A Community Based High Risk Register for Hearing Loss

1982 ◽  
Vol 47 (4) ◽  
pp. 373-375 ◽  
Author(s):  
James L. Fitch ◽  
Thomas F. Williams ◽  
Josephine E. Etienne
Keyword(s):  
Hearing Loss ◽  
System Identification ◽  
High Risk ◽  
Language Learning ◽  
Education Program ◽  
Communication System ◽  
Auditory Signal ◽  
Early Age ◽  
Community Based ◽  
Children With Hearing Loss

The critical need to identify children with hearing loss and provide treatment at the earliest possible age has become increasingly apparent in recent years (Northern & Downs, 1978). Reduction of the auditory signal during the critical language-learning period can severely limit the child's potential for developing a complete, effective communication system. Identification and treatment of children having handicapping conditions at an early age has gained impetus through the Handicapped Children's Early Education Program (HCEEP) projects funded by the Bureau of Education for the Handicapped (BEH).

Sign in / Sign up

Export Citation Format

Share Document