AASHTO T 271-83 (2004) PDF Download

AASHTO T 271-83 (2004) is a standard method of test that outlines the procedures for determining the density of plastic and hardened Portland cement concrete in-place using nuclear methods. The standard describes two methods - Direct Transmission and Backscatter.

The Direct Transmission method involves measuring the gamma radiation passing through a known volume of concrete using a special instrument. This method is typically used for concrete that is less than 10 inches thick. The density of the concrete is calculated based on the attenuation of the gamma radiation.

The Backscatter method, on the other hand, involves measuring the gamma radiation reflected back from the surface of the concrete. This method is typically used for concrete that is more than 10 inches thick. The density of the concrete is calculated based on the backscattered gamma radiation.

Both methods require the use of a nuclear instrument, such as a gamma radiation source and detector, to measure the radiation. The standard provides detailed instructions on the equipment setup, calibration, and measurement procedures to ensure accurate and reliable results.