Dana Dashti

Date of Graduation

2016

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

Roger Chen

Committee Co-Chair

Radhey Sharma

Committee Member

P V Vijay

Abstract

In this study, two nondestructive testing (NDT) techniques were investigated to study the ultrasonic pulse velocity and water cement ratio of self-consolidating concrete (SCC) and traditional vibrated concrete (TVC). The ultrasonic pulse velocity test is one of the most useful nondestructive methods to determine the properties of concrete. It is also important in structural engineering where it can detect defects and determine deterioration. In order to reach these purposes, there are several ultrasonic wave propagation characteristics that should be taken under consideration such as: velocity, attenuation, frequency, and energy. For the purpose of this study, 3 specimens from each mix design batch of conventional and self-consolidating concrete were tested in the laboratory at 1, 3, 7, 14, and 28 days after their casting to measure the pulse velocity and the compressive strength. The relationship between the pulse velocity and Young's modulus of those concrete specimens was determined. The ultrasonic pulse velocity test can be performed with a simple setting that includes: two transducers, a pulser-reciever unit, and the data acquisition system. The two transducers were to conduct direct transmission. Test results showed that dynamic Young's modulus could be obtained from the wave velocity measurement but the dynamic Young's modulus is higher than those static Young's modulus calculated from the compressive strength for both conventional and self-consolidating concrete. The results also show that self-consolidating concrete has higher compressive strength at early ages compared to conventional concrete.;Since the self-consolidating concrete (SCC) is highly influenced by the changes in water content, it is important to develop on-site methods to determine water to cement ratio, which would be useful for on-site applications. In this thesis, the standard method for water content of freshly mixed concrete using microwave method was tested on both conventional concrete and SCC to determine their on-site water to cement ratio. Two testing procedures were used following AASHTO T318-02, which included the use of non-sieved concrete samples and sieved concrete sample. Both methods were used to determine the w/cm ratio for the conventional Fly Ash concrete and SCC with different accuracy ranges between the two. The average error for TVC is 5.13% and for SCC is 10.35% using non-sieved concrete samples. However, the results showed that the current method using sieved concrete samples would not provide the same accuracy. The modified method using sieved concrete samples for both SCC and conventional concrete samples provided higher error because the sieved method provides an inaccurate amount of cement powder being extracted.

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