Large scale concrete specimen for validation

For efficient use of non-destructive testing methods in civil engineering (NDT-CE) the reliability and limits of testing methods must be known. This is the pre-condition to give a statement concerning stability, safety to traffic and durability. To meet the demand of method comparison and damage assessment BAM has established a real-size reinforced concrete slab.

Practical experience in NDT-testing for more than ten years and urgent research topics from our own investigations and applications have defined its construction. The concrete slab has an area of 10 x 4 m² with a regular thickness of 30 cm. The large dimensions of the specimen are necessary to minimize boundary effects on the measured signals and to establish well-defined defects with varying properties. Measurements on a specimen in real size scale contribute to the development of NDT-CE methods. Furthermore these methods will be adapted to on-site conditions.

The concrete slab is partitioned in two sections separated by a joint with anchors. Ten meters long ducts in a distance 30 cm below the subsurface allow radiography for a detailed reference testing.

One section contains tendon ducts with different diameters and concrete cover. The ducts contain a different number of strains. Well-defined areas with grouting defects along the prestressing steel have been implemented. The other section provides areas with varying thickness and voids. Auxiliary elements such as thermoelements, water inlet and reinforcement mats are implemented.

To gain full information about an investigated area a scanner system has been designed allowing high resolution testing. The scanner-system can be used for automated impact echo, ultrasonic echo and radar measurements. The well-defined location of voids and geometry allows method comparison and combination (data fusion) as well as calibration of measurement devices. The LCS is accessible to everyone concerned with NDT to test his equipment.

The concept allows establishing the slab as a reference test specimen. The use of the slab for measurements and data analysis is also possible as validation of NDT-CE methods.

Arrangements for the use of the large concrete specimen (LCS) can be made with the contact persons.

top