Use of ultra-high performance concrete to mitigate impact and explosive threats

This study is a continuation of research conducted by Natalia Carey, Anthony Wulfers, and Dr. John Myers under the DHS ALERT Center. Carey investigated the use of polyurea coating systems to mitigate close range blast threats on wall panels. Wulfers continued this by using both polyurea coatings as well as a sacrificial wood fiber fly ash (WF-FA) layer to try to get increased performance.;This research was aimed at the study of ultra-high performance concrete (UHPC) for the use in impact and blast mitigation. There is little information on the performance of UHPC under close range blast loading; therefore it was the goal of this project to determine the performance of UHPC when undergoing a close range blast threat, as well as to determine if an ultimately thinner wall section could outperform systems previously tested by Carey (2012) and Wulfers (2012). Three panel systems were examined with differing levels of fiber content; no fiber, 2% fiber by weight, and 6% fiber by weight. One aspect of interest in this study was to determine the impact of fiber content on the effectiveness of the panel under blast loading. The panels used in this research were tested at the Missouri S&T Experimental Mine, and the damage was reported both visually as well as quantitatively. Visual inspection was used to compare the overall level of damage. Quantitative results, such as mass loss and residual deflections, were used to determine the effectiveness of the wall system in mitigating the blast event. After examining the results, it is shown that UHPC without fiber does not perform well under this type of loading, but that increasing fiber content did increase performance of the wall panel in equivalent blast events. It is also shown that this material undergoes minimal spalling and fragmentation which is favorable for structures that are at risk to blast events. There is also little information on the performance of UHPC under impact loading. As such, this work also included testing to determine the impact capabilities of this material and compare the performance of UHPC panels to other types of high performance concrete systems that have undergone impact testing at Missouri S&T by Gliha (2011).