University of New Mexico

Civil Engineering Department

Civil Engineering Materials Laboratory, CE 305L

PULSE VELOCITY THROUGH CONCRETE

ASTM C597

Scope

This ASTM test method covers the determination of the pulse velocity of propagation of compressional waves in concrete. The pulse velocity is related to the physical properties of a solid by the equation:

where:

a constant,

the modulus of elasticity, and

the mass density.

This test method does not apply to the propagation of other vibrations within the concrete

Summary of Method

Pulses of compressional waves are generated by an electro-acoustical transducer that is held in contact with one surface of the concrete under test. After traversing through the concrete, the pulses are received and converted into electrical energy by a second transducer located a distance from the transmitting transducer. The transit time is measured electronically. The pulse velocity is calculated by dividing by .

Related Non-Destructive Test (NDT) Procedures

ASTM C215 Standard Test Method for Fundamental Transverse, Longitudinal, and Torsional Frequencies of Concrete Specimens

ASTM C805 Standard Test Method for Rebound Number of Hardened Concrete

Apparatus

Ultra Sonic Tester - The testing apparatus , shown schematically in Figure 1, consists of a pulse generator, a pair of transducers (transmitter and receiver), an amplifier, a time measuring circuit, a time display unit, and connecting cables. The PUNDIT ultrasonic concrete tester incorporates all of the above-described features.

Figure 1. Schematic of Pulse Velocity Circuit.

Concrete Specimen - 6” diameter by 12” long

Procedure

Download Procedure for Pulse Velocity

Download Excel form for Pulse Velocity

1) Check the accuracy of the transmit time measurement against the calibration bar. Use an appropriate coupling agent (e.g., vacuum grease, petroleum jelly, or other viscous material) between the transducers and the ends of the calibration bar. Adjust the PUNDIT ultrasonic tester so that the transit time is the same as that stamped on the calibration bar.

Figure 2. Photo of Procedure

2) Measure the length of the concrete specimen.

3) Determine the mass of the concrete specimen.

4) Apply the appropriate coupling agent to the transducers and the test surfaces (the ends of the cylindrical specimen) in order to avoid entrapped air between the contact surface of the transducers and the concrete surface.

5) Press the faces of the transducers against the surfaces of the concrete (cylindrical ends) assuring good contact.

6) Measure the transit time.

Calculation

1) Calculate the pulse velocity as follows:

V = L / T

where:

V = pulse velocity, m/s,

L = distance between transducers, m, and

T = transit time, s.

2) Calculate the modulus of elasticity as follows:

where:

E = the modulus of elasticity, Pa (N/m²),

V = pulse velocity, m/s,

ρ = the mass density, kg/m³, and

K = 1 (for a cylindrical specimen tested as above).

Report

1) Specimen description and location of transducers.

2) Distance between transducers.

3) Transit time.

4) Pulse velocity.

5) Mass density of specimen.

6) Modulus of elasticity (nearest 50,000 psi).

Questions

1. What is the value of E in pounds per square inch? (Note: 0.3048 m = 12 in. = 1 ft, 4.448 N = 1 lb)

2. How does the non-destructive determination of the Modulus of Elasticity compare with that determined by ASTM Test Method C469 (Static Modulus of Elasticity of Concrete in Compression)? What is the % difference between these two measurements? Which one is greater in value? Explain the difference.