Monday  |  Lakeshore A  |  10:40 AM–11:00 AM

#19103, The Influence of Entrained Air on the Dynamic Compressive Performance of Conventional Concrete

Freeze-thaw damage is a common form of deterioration in concrete that happens when it is subjected to frequent cycles of freezing and thawing, mainly in cold weather. This kind of damage mostly affects the durability of concrete, causing scaling, cracking, and spalling that over time can compromise the structural integrity. One of the useful approaches to decreasing freeze-thaw damage is by adjusting permeability, such as introducing entrained air in the concrete mix acting as pressure-relief zones when water inside the concrete freezes and expands. This method does not directly reduce permeability but mitigates the influence of any water entrapped in the concrete. Understanding the relationship between the entrained air percent and dynamic behaviors of concrete facilitates more effective use of materials. By studying this connection, designers can determine the acceptable percentage of air that doesn’t significantly compromise the concrete’s performance. It is therefore the goal of this study to answer the question: To what extent can air content affect the dynamic compressive performance of conventional concrete? Subsequently, cylindrical specimens with different air content percentages were developed and tested under dynamic strain rates. For the dynamic testing, a 2-inch diameter Kolsky compression bar system with well-designed pulse shapers was used to enable the constant strain rate deformation and dynamic stress equilibrium conditions. The results revealed that the air content imposes significant impacts on the dynamic compressive performance of conventional concrete.

Mahmoud Awd Allah   Southern Methodist University
Mohamed Abbas   Southern Methodist University
Brett Williams   Army Engineer Research and Development Center
William Heard   Army Engineer Research and Development Center
Xu Nie   Southern Methodist University