Blast and impact response of elastomer-coated concrete

With global security concerns at the forefront of political and industrial agendas, growing attention is being focused on strategies to protect critical infrastructure from the detrimental effects of blast and impact. While new structures can be designed with this threat in mind, existing, ageing infrastructure remains vulnerable. Structural retrofit for blast and impact mitigation is one solution to this problem. This work considers one practical, cost-effective retrofit solution: the application of a spray-on elastomer coating to concrete structural elements. While encouraging results have been reported in the literature for masonry and steel substrates, it remains to be understood if, and by what mechanism this retrofit can enhance the blast and impact resistance of concrete structures. The objective of this work is to understand the blast and impact response of elastomer-coated concrete and hence, to establish design guidelines, informing on effective implementation of this retrofit solution. The response characteristics of concrete and elastomer materials are established and modelled across a range of stress states and loading rates, from quasi-static to dynamic. Numerical modelling and analytical techniques are used to interrogate the blast response of elastomer-coated concrete targets. It is found that commercially available coatings are most effective in regimes where there is severe blast-induced concrete damage, though they offer limited benefit during fluid-structure interaction and during dynamic flexure. Next, high speed experimentation is performed to assess the impact response of elastomer-coated concrete. The addition of a coating contributes a significant protective benefit in this regime. Numerical models are developed and used to establish the mechanisms of protection. Finally, simple analytical models are proposed, which reveal key parameter sensitivities, thus informing on effective coating design for concrete impact damage mitigation.The authors are grateful for the financial support of the George and Lillian Schiff Foundation of the University of Cambridge