SBIR-STTR Award

Rapid Assessment of Air Void System in Fresh Concrete
Award last edited on: 9/27/2022

Sponsored Program
SBIR
Awarding Agency
DOT
Total Award Amount
$614,926
Award Phase
2
Solicitation Topic Code
17.1-FH2
Principal Investigator
Xiogjun Wu

Company Information

Dynaflow Inc

10621-J Iron Bridge Road
Jessup, MD 20794
   (301) 604-3688
   info@dynaflow-inc.com
   www.dynaflow-inc.com
Location: Single
Congr. District: 02
County: Howard

Phase I

Contract Number: DTRT5717C10171
Start Date: 5/30/2017    Completed: 12/29/2017
Phase I year
2017
Phase I Amount
$104,927
Air parameters such as specific surface (SS) and spacing factor (SF) are essential in evaluating Freeze-Thaw (F-T) durability in fresh concrete. Currently there is no method or device that can accurately meet such requirements. We propose to develop an acoustic air void measurement system that can be used in the field to measure in near real time air void distributions in fresh concrete. The proposed solution is based on the fact that air bubbles are very sensitive to acoustic excitation. The instrument will measure as functions of frequency the properties of the acoustic propagation in terms of sound speed and attenuation, which change with the void distribution. Using mathematical relationships between the acoustic properties of the fresh concrete and the size distributions of air voids, an inversion procedure extracts the bubble size distribution. From this the specific surface and spacing factor of the air void system in fresh concrete that are important to determine the concrete’s F-T durability will be deduced. The instrument will provide rapid and accurate assessment of these parameters and will be easy to operate.

Phase II

Contract Number: 6913G618C100009
Start Date: 00/00/00    Completed: 00/00/00
Phase II year
2018
Phase II Amount
$509,999
Air void parameters such as specific surface (SS) and spacing factor (SF) are essential in evaluating Freeze-Thaw (F-T) durability in fresh concrete. We have demonstrated the feasibility and viability of using an acoustic method to measure in near real time air void distributions in fresh concrete, the proposed solution is based on the fact that air bubbles are very sensitive to acoustic excitation. By further enhancing the robustness and accuracy of the acoustic method, improving the portability of the design, and conducting extensive field validation and improving the design based on feedbacks, we will have a field ready prototype system for air void measurement through this project. This robust and compact instrument will provide rapid and accurate assessment of air void parameters of fresh concrete wherever the information is needed.