Capillary Pressure Monitoring in Plastic Concrete for Controlling Early-Age Shrinkage Cracking

2014 ◽  
Vol 2441 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Volker Slowik ◽  
Markus Schmidt ◽  
Daniel Kässler ◽  
Michael Eiserbeck
Keyword(s):  
Capillary Pressure ◽  
Early Age ◽  
Pressure Monitoring ◽  
Shrinkage Cracking ◽  
Plastic Concrete

scholarly journals Early-Age Thermal-Shrinkage Cracking in Deep Foundations

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Łukasz Grabowski ◽  
Monika Mitew-Czajewska
Keyword(s):  
Thermal Shrinkage ◽  
Future Research ◽  
Early Age ◽  
Deep Foundations ◽  
Shrinkage Cracking ◽  
The United Kingdom ◽  
Normative Requirements ◽  
Geotechnical Design ◽  
European Standards ◽  
Materials Used

Abstract With the growing rate of urbanisation, deep foundations are playing an ever-larger role in the development of cities, reaching deeper than before to fulfil the requirements of new constructions. While current European standards include design procedures for structural and geotechnical design, they lack provisions for massive deep foundations with regard to early-age thermal effects. This paper presents aspects of the phenomenon especially important for deep foundations and discusses normative requirements that influence their thermal behaviour. Further, the paper describes the methods and results of the research carried out in the United Kingdom on 1.50-m-thick diaphragm walls of a deep circular shaft. Shaft features are described, as well as the materials used. The measurements were carried out using vibrating wire strain gauges coupled with temperature readings. The results presented refer to one of the test panels concreted in January 2020. The temperature results are analysed together with the influence of work scheduling on the readings. Strain results that indicate contractive behaviour of the test panel are investigated together with the possible causes leading to such readings. Plans and directions for future research are discussed.

Early age shrinkage cracking of restrained metakaolin-slag-palm oil fuel ash binder geopolymer mortars

2018 ◽  
Vol 7 (5) ◽  
pp. 271-295 ◽  
Author(s):  
Ali Mohamed Ali Aboshia ◽  
Riza Atiq Rahmat ◽  
Muhammad Fauzi Mohd Zain ◽  
Amiruddin Ismail
Keyword(s):  
Palm Oil ◽  
Early Age ◽  
Shrinkage Cracking ◽  
Palm Oil Fuel Ash ◽  
Fuel Ash ◽  
Oil Fuel

An Evaluation on the Restrained Shrinkage of Ultra-High Performance Concrete

2012 ◽  
Vol 525-526 ◽  
pp. 449-452 ◽  
Author(s):  
Jung Jun Park ◽  
Doo Yeol Yoo ◽  
Sung Wook Kim ◽  
Young Soo Yoon
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Tensile Creep ◽  
Ring Test ◽  
Early Age ◽  
Restrained Shrinkage ◽  
Reinforcing Bars ◽  
Ultra High Performance Concrete ◽  
Shrinkage Cracking ◽  
Coarse Aggregates

Since ultra-high performance concrete (UHPC) is subject to large occurrence of shrinkage at early age due to its low water-to-cement ratio, the mixing of large quantities of powdered admixtures and the absence of coarse aggregates, UHPC presents large risks of shrinkage cracking caused by the restraints provided by the form and reinforcing bars. Accordingly, this study intends to evaluate the shrinkage behavior of UHPC under restrained state by performing restrained shrinkage test using ring-test. The test results reveal that increasing thickness of the inner ring increases the tensile creep at early age leading to the reduction of the average strain and residual stress of the inner ring.

Influence of Ultrafine Fly Ash on the Early Age Response and the Shrinkage Cracking Potential of Concrete

2005 ◽  
Vol 17 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Kolluru V. Subramaniam ◽  
Roman Gromotka ◽  
Surendra P. Shah ◽  
Karthik Obla ◽  
Russell Hill
Keyword(s):  
Fly Ash ◽  
Early Age ◽  
Shrinkage Cracking ◽  
Cracking Potential

scholarly journals Restrained Stress Development in Hardening Mortar Internally Cured with Superabsorbent Polymers under Autogenous and Drying Conditions

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 979
Author(s):  
Jung Heum Yeon
Keyword(s):  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Early Age ◽  
Shrinkage Cracking ◽  
Stress Development ◽  
Cracking Potential ◽  
Different Types ◽  
Internal Relative Humidity ◽  
Series Of Experiments ◽  
Drying Conditions

This study reports the results of a series of experiments, particularly paying attention to the early-age behavior and response of hardening mortars incorporating different types and contents of superabsorbent polymer (SAP) under autogenous (sealed) and drying shrinkage (unsealed) conditions. To achieve this primary aim, the effects of SAP type (i.e., cross-linking density and grain size) and content on the internal relative humidity (IRH) changes and corresponding free shrinkage behavior, restrained stress development, and cracking potential of the mortar were extensively measured and analyzed, along with their strength and set time properties. The results of this study have shown that the internal curing (IC) via SAP effectively counteracted the early-age residual stress build-up due to autogenous shrinkage, as many other former studies described. No or little tensile residual stresses due to autogenous shrinkage took place when more than 0.4% SAP was added, regardless of the SAP type. However, it should be mentioned that the addition of SAP, irrespective of its content and type, hardly improved the shrinkage cracking resistance of the mortar when directly exposed to drying environment at early ages.

The Effects of Water-Reducer on Early-Age Plastic Shrinkage of Concrete

2012 ◽  
Vol 174-177 ◽  
pp. 1113-1118
Author(s):  
Hong Gen Qin ◽  
Zhi Hua Fei ◽  
Wei Guo ◽  
Qian Tian
Keyword(s):  
Capillary Pressure ◽  
Evaporation Rate ◽  
Mechanical Performance ◽  
Important Influence ◽  
Early Age ◽  
Cracking Resistance ◽  
Plastic Shrinkage ◽  
Effect Of Water ◽  
Better Than

Water-reducer is one of the dispensable components in modern concrete, can improve the workability and mechanical performance of concrete, and also has an important influence on the plastic cracking resistance of concrete. In this paper, the flat cracking test was used to evaluate the effect of water reducer on the plastic cracking resistance of concrete, meanwhile, capillary pressure; plastic settlement and evaporation rate were also tested. The results showed that water-reducer could improve the plastic cracking resistance of concrete significantly, and the effectiveness of polycarboxylate water reducer were o better than that of wood calcium and naphthalene water reducer.

scholarly journals A Mesoscopic Simulation for the Early-Age Shrinkage Cracking Process of High Performance Concrete in Bridge Engineering

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Guodong Li ◽  
Zonglin Wang
Keyword(s):  
High Performance ◽  
Damage Mechanics ◽  
High Performance Concrete ◽  
Bridge Engineering ◽  
Early Age ◽  
Crack Model ◽  
Shrinkage Cracking ◽  
Mesoscopic Simulation ◽  
Shrinkage Cracks ◽  
Cracking Process

On a mesoscopic level, high performance concrete (HPC) was assumed to be a heterogeneous composite material consisting of aggregates, mortar, and pores. The concrete mesoscopic structure model had been established based on CT image reconstruction. By combining this model with continuum mechanics, damage mechanics, and fracture mechanics, a relatively complete system for concrete mesoscopic mechanics analysis was established to simulate the process of early-age shrinkage cracking in HPC. This process was based on the dispersion crack model. The results indicated that the interface between the aggregate and mortar was the crack point caused by shrinkage cracks in HPC. The locations of early-age shrinkage cracks in HPC were associated with the spacing and the size of the aggregate particle. However, the shrinkage deformation size of the mortar was related to the scope of concrete cracking and was independent of the crack position. Whereas lower water to cement ratios can improve the early strength of concrete, this ratio cannot control early-age shrinkage cracks in HPC.

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