Strength-related testing of concrete using microwave signals
US5939889A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 7, 1993 |
| Grant date | Aug 17, 1999 |
| Priority date | — |
| Expiry date | May 7, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N33/28
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus is disclosed for testing concrete having an unknown water/cement ratio and an unknown compressive strength. The apparatus includes a transmitter assembly for transmitting microwave signals at one or more predetermined frequencies. A receiver assembly receives each microwave signal reflected from the concrete under test. The reflected microwave signals, together with the transmitted microwave signals, are used to determine a reflection coefficient magnitude for the particular microwave frequency. A processing unit uses the reflection coefficient magnitude to determine a value related to concrete strength. In one embodiment, the processing unit relies on a logarithmic function that correlates the reflection coefficient magnitude and a water/cement ratio. A value related to the compressive strength of the concrete can also be obtained using the value of the water/cement ratio or the value of the reflection coefficient magnitude.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.