Title page for ETD etd-06062008-170019

Type of Document Dissertation
Author Al-Akhras, Nabil M.
URN etd-06062008-170019
Title Characterization and deterioration detection of portland cement concrete using ultrasonic waves
Degree PhD
Department Civil Engineering
Advisory Committee
Advisor Name Title
Al-Qadi, Imadeddin L. Committee Chair
Barker, Richard M. Committee Member
Cramer, Mark S. Committee Member
Duke, John C. Jr. Committee Member
Walker, Richard D. Committee Member
  • nondestructive evaluation
Date of Defense 1995-11-10
Availability restricted

An experimental study was conducted to characterize Portland cement concrete (PCC), to detect deterioration induced by freeze/thaw and alkali-silica reaction, and to detect chloride presence in PCC using ultrasonic waves. The experimental program was initiated to investigate the effect of water to cement (w/c) ratio, aggregate type, and air entrainn1ent on measured ultrasonic wave velocity and signal energy. Three w/c ratios (0.35, 0.45, and 0.55) were evaluated. Two aggregate types, quartzite and limestone, were included in the PCC mixes separately. Mixes were prepared as non-air entrained and air entrained. Thus, a total of twelve batches were prepared to evaluate PCC using ultrasonic waves at two frequencies, 54 and 340 kHz.

The experimental program to investigate freeze/thaw (FT) damage included the effect of curing time, w/c ratio, and aggregate type. The effect of curing time was investigated by exposing PCC specimens cured for 3 and 7 days to FT. Two w/c ratios were considered, 0.45 and 0.55. The effect of aggregate on detecting FT damage was investigated using two types of crushed stone aggregate, quartzite and limestone. Alkali-silica reaction (ASR) damage was investigated uSIng two w/c ratios, 0.35 and 0.45. Embedded composite strain gages were used to monitor the ASR deleterious deterioration. High alkali cement and active silica aggregate were used to produce ASR.

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