Course: Non Destructive Concrete Tests Subject:

Dynamic modulus of elasticity ASTM C215-91

Prepared by : Hisham Shehadeh Shehadeh

ID# : 201302031

Submitted to : Dr.Oussama Baalbaki

Dynamic modulus of elasticity is the ratio of stress to strain under vibratory conditions (calculated from data obtained from either free or forced vibration tests, in shear, compression, or elongation).

ASTM-C215 or Resonant frequency test allows the determination of Ed

Ed is known to be different (higher) from that obtained by direct static testing of a cylinder drawn from the structure.

Resonance Frequency test allows us to determine :

Dynamic elastic properties (modulus of elasticity, poisson ratio, shear modulus of elasticity).

Monitoring damage as a result of exposure to accelerated weather.

Quality Control of manufactured products

Resonance frequency meter :

Features : LCD 7" Touch screen integrated monitor Integrated PC card Software utility for positioning of measuring and impact points Automatic measurement of resonance frequencies values Display of harmonic frequencies USB, LAN and VGA interfaces Storage of data on USB memory RES - Lab software included

Measuring Principle

1. An acoustic vibrator is positioned on one side of the specimen 2. An accelerometer is mounted on another side. 3. A generator drives the acoustic vibrator at a given frequency 4. The vibration of the specimen is measured by the accelerometer.

5. The frequency of the acoustic vibrator is varied continuously. 6. The corresponding amplitude of specimen vibration is monitored. 7. When the specimen is driven at its resonant frequency fr - the

amplitude of specimen vibration is at its maximum.

Calculation of Ed :

For longitudinal mode in kg/cm 2 : Where W = weight of specimen (kg) fLr = longitudinal frequency (Hz) Dcylinder = 519.4x10-5 L/d 2 (sec 2/cm 2 ) Dprism = 408x10-5 L/bt (sec 2/cm 2 ) L = length of specimen in cm b,t = dimensions of cross section of prism in cm

Ed=

Or Ed =DW(fLr)^2

Thank YOU