# Experimental and Numerical Evaluation of Calcium-Silicate-Based Mineral Foam for Blast Mitigation
## 1 Introduction  
As a consequence of the escalating occurrence of terrorist attacks and accidental explosions over the preceding decades, it has become imperative to implement preventive measures and make use of blast-resistant techniques to safeguard the structural integrity and survivability of infrastructures. The main idea of blast protection involves interposing a structure between a target and a detonation point [1]. This structure is engineered to achieve several objectives, including mitigating explosive detonation [2; 3; 4], disrupting blast wave propagation [1; 5; 6; 7; 8], or providing passive target protection [9; 10; 11; 12; 13; 14; 15; 16]. Bulk water [2], mist [3], or aqueous foam [4] are some of the strategies for mitigating explosive detonation. Conversely, materials of various layers exploit impedance mismatches between layers to disperse the blastwave throughout the structure [5]. Geometry-based designs, including V-shaped plates [6], arrays of cylindrical pipes [7], or three-dimensional grid panels [1], can deflect or disrupt incoming blast waves. Sacrificial cladding (SC) is a passive protective measure that dissipates blast wave energy, enhancing target protection against blast loading [17]. It comprises a crushable core sandwiched between the target structure and a front skin [17; 18]. The front skin is meant to evenly distribute blast pressure onto the crushable core, facilitating uniform compression [10; 17; 19]. The deformation of the crushable core occurs progressively under constant low stress relative to the target's resistance, absorbing most of the blast-induced energy and potentially protecting the target [20]. Various types of crushable cores with diverse topologies have been proposed, including tubular configurations [21; 22; 23], honeycomb structures [24; 25; 26; 20], auxetic cores [24; 27; 28; 29] or cellular solids such as metallic [30; 31; 32; 33], polymeric [16; 17; 34; 35], or mineral foams [36; 37; 38; 39]. The findings of these studies demonstrate that the SC, incorporating these different core types, exhibits significantly higher energy dissipation capabilities in comparison to the unprotected structure [40]. Moreover, comprehensive investigations through experimental studies and numerical simulations have been conducted to thoroughly explore SC's energy dissipation, response, and failure modes under blast loads. [PERSON] and [PERSON] [9] have developed a load-cladding structure model (LCSM) to assess the foam cladding's protective effects on main structures subjected to blast loads. This model uses a single degree of freedom (SDOF) system. In the LCSM, the applied blast loading is assumed to be identical both with and without the sacrificial cladding, as the foam's thickness is negligible compared to the standoff distance. Additionally, two nondimensional parameters are introduced to characterize the relationship between the foam cladding and the protected structure. The investigation revealed that significant improvement in structural resistance against blast loads could be achieved by wisely considering the strength compatibility between the protected structure and the foam core. For instance, SC made of an aluminum foam to reduce blast effects on a simply supported reinforced concrete slab was used by [PERSON] et al. [30]. They evaluated the effectiveness of aluminum foam protection using an SDOF model and a full-field experiment. Results revealed partial compaction of the aluminum foam and significant cracking in the slab throughout its depth and length. The observed results were attributed to the high plateau stress transmitted to the slab. Addressing the issue of strength mismatch between the protected structure and the foam core, [PERSON] et al. [31] proposed a solution involving a graded core density. Various front skin materials (steel alloy, aluminum alloy, and carbon fiber-reinforced plastic--CFRP) with 1 mm thickness were used when conducting the blast tests.