Degree Type

Dissertation

Date of Award

2005

Degree Name

Doctor of Philosophy

Department

Civil, Construction, and Environmental Engineering

First Advisor

Kejin Wang

Abstract

Concrete temperature and strength development is essential to in-service concrete performance. Undesirable temperature development may cause concrete to crack under some environmental conditions, and it may result in insufficient strength development. Concrete strength is important for construction operations, such as joint cutting and pavement opening time.;In this study, heat signature and maturity-strength tests were conducted on 23 different concrete mixes. A semi-adiabatic calorimeter was used for the heat signature test. Based on the test data, as well as the data from cited literature, a combined model for predicting temperature and strength development of concrete pavement under various construction and environmental conditions is presented. Using commercial finite-element software, FEMLAB (Finite Element Modeling Laboratory), the model can well predict the temperature and strength distributions inside a concrete pavement with time.;In the proposed temperature model, concrete temperature development was determined based on the heat of hydration of cementitious materials and the field environmental conditions of pavement. The general heat of hydration model was developed to predict heat of hydration of cementitious materials. The heat exchange between the pavement and environment was computed based on the transient heat transfer mode of FEMLAB. Material variables, pavement structure variables, and environmental variables were considered.;The modified maturity-strength model was developed based on the laboratory and literature data. The model considers the effects of the cement chemical and physical properties, amount and chemical composition of fly ash and slag, water/cement ratio, air content and curing conditions.;The integrated model was applied to study field concrete temperature and strength development under two different field conditions. The included analyses indicate that the modeling results well correlated with the experimental results. The new model can be used to optimize concrete mix design, to assess field concrete strength development, and to select optimal concrete placement temperature and construction conditions for minimal thermal stress.

DOI

https://doi.org/10.31274/rtd-180813-15373

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Zhi Ge

Language

en

Proquest ID

AAI3200417

File Format

application/pdf

File Size

215 pages

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