Concrete Slab Evaluations

Voids beneath a concrete slab pose a danger to safety and may cause costly damage to a structure if not repaired in time. ACER utilizes Ground Penetrating Radar (GPR), Impact Echo, and Slab Impulse Response technology to evaluate slab thickness and condition, as well as quickly and efficiently identify and map the extent of subgrade voids beneath concrete slabs. When combined, these technologies can identify areas of damaged concrete (cracking, honeycombing, delaminating, voids, etc.), and can also be used to assess sub slab repairs when comparing data collected before and after repairs are made.

ACER utilizes the GSSI StructureScan Mini XT, an all-in-one GPR system is designed specifically for the concrete inspection industry. It utilizes a 2700 MHz center frequency and reaches depths up to twenty-four inches (24 inches). An auxiliary 2300 MHz antenna attachment allows ACER to reach even tighter spaces or overhead areas with ease, and can easily be set-up to perform cross-polarized scans in order to better see non-metallic targets as well as the bottom of the slab. Due to the signal response resulting from encountering air (voids), ACER can delineate the extent of voids beneath a concrete slab.

Depending on the conditions of the slab, Impact Echo (IE) and/or Slab Impluse Response (SIR) technologies can be utilized on reinforced and nonreinforced concrete slabs, as well as asphalt or asphalt overlay slabs. By striking the slab with an instrumented hammer or impactor adjacent to an accelerometer in contact with the slab, low-stiffness areas associated with hidden damage such as voids, honeycombing, and cracking can easily be identified and delineated. This technology allows for fast testing from just one side of the slab. Surveys can be conducted prior to and after concrete repairs to confirm repairs have been completed to spec, or to identify any shortcomings in the repair efforts.