Analytical and quantitative aspects of surface moisture transport and plastic shrinkage cracking

B. Mobasher, M. Bakhshi, Y. Yao

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The drying rate of porous materials such as hydrating cement paste during early hydration stages is studied using analytical and experimental procedures. Effects of micro and macro fibers as they change the nature of restrained shrinkage cracking are also documented. A methodology based on vacuum drying experiments is developed to measure the rate of evaporation from the surface of fresh paste and mortar mixtures that leads to restrained shrinkage cracking. Stages of microcrack coalescence due to plastic shrinkage cracking are quantitatively analyzed using digital image correlation. A model for internal moisture transfer simulates initial constant drying rate followed by a vapor diffusion transport phenomena. A fluid mechanics approach for water evaporation from the boundary-layer in terms of mass transfer, diffusion, and convection is used. Effect of temperature, wind speed, and relative humidity are studied. Results of these two experiments are then integrated with an analytical approach for the restrained ring specimen which correlates the moisture diffusion in the specimen with the rate of evaporation and shrinkage strain. The model incorporates key influential parameters of diffusion, evaporation, shrinkage, creep, aging, and microcracking, in the stress analysis of a restrained concrete section. The formulation addresses the effect of geometry of the specimen, the humidity and shrinkage conditions, and the restraint offered by stiffness of the steel ring. Finally the modelling is extended to simulate a slab on ground and predict multiple transverse cracking as well as slab curling using a finite difference model.

Original languageEnglish (US)
Title of host publication6th International Conference on Durability of Concrete Structures, ICDCS 2018
EditorsP. A. Muhammed Basheer
PublisherWhittles Publishing Limited
Pages74-82
Number of pages9
ISBN (Electronic)1849953945, 9781849953948
StatePublished - Jan 1 2018
Externally publishedYes
Event6th International Conference on Durability of Concrete Structures, ICDCS 2018 - Leeds, United Kingdom
Duration: Jul 18 2018Jul 20 2018

Publication series

Name6th International Conference on Durability of Concrete Structures, ICDCS 2018

Conference

Conference6th International Conference on Durability of Concrete Structures, ICDCS 2018
CountryUnited Kingdom
CityLeeds
Period7/18/187/20/18

Keywords

  • Cracking
  • Diffusion
  • Drying
  • Modeling
  • Moisture transport
  • Restrained shrinkage

ASJC Scopus subject areas

  • Mechanics of Materials
  • Safety, Risk, Reliability and Quality
  • Materials Science(all)
  • Building and Construction

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  • Cite this

    Mobasher, B., Bakhshi, M., & Yao, Y. (2018). Analytical and quantitative aspects of surface moisture transport and plastic shrinkage cracking. In P. A. M. Basheer (Ed.), 6th International Conference on Durability of Concrete Structures, ICDCS 2018 (pp. 74-82). (6th International Conference on Durability of Concrete Structures, ICDCS 2018). Whittles Publishing Limited.