Performance of hybrid cement composite elements under drop-weight impact load

Abstract

ABSTRACT:The performance, under drop-weight impact load, of hybrid cement composite (HCC) elements, consisting of a top layer of plain concrete (PC) and a bottom layer of fibre reinforced concrete (FRC), in comparison with full-depth FRC and PC was studied. Apart from improving the tensile capacity of PC and saving fibre steel reinforcements of FRC, the results showed that HCC can effectively control the deformations and enhance the impact performance of the structural members as its outcomes were similar to that of a full-depth FRC. The analytical studies using Hughes empirical formulae (HEF) and yield line theory (YLT) adopted to investigate the practical use of HCC showed that they are applicable for design such HCC elements against impacts. KEYWORDS: RESUMEN:Comportamiento de elementos estructurales de compuestos híbridos base cemento frente a impacto de torre de caída. Se estudió el comportamiento, frente a impacto de torre de caída, de elementos híbridos base cemento (HCC), formados por una capa superior de hormigón en masa (PC) y una capa inferior de hormigón reforzado con fibras (FRC) en comparación con elementos análogos íntegramente fabricados con FRC y PC. Además de proporcionar una mejora en la resistencia frente a flexo-tracción de los PC y un ahorro en refuerzo usando fibras de acero en el caso de los FRC, los resultados mostraron que el HCC puede controlar eficazmente las deformaciones y mejorar el rendimiento frente a impacto de los elementos estructurales ya que sus resultados fueron análogos a la de los FRC. Los estudios analíticos, utilizando HEF e YLT, adoptados para investigar el uso práctico de los HCC mostraron que los mismos son aplicables para el diseño de estos elementos frente a impacto.

Mechanical behaviour of laminated functionally graded fibre-reinforced self-compacting cementitious composites

“…However, the recent study, performed by Enfedaque [Enfedaque, 2008] and Nguyen et al [Nguyen et al, 2014] using the same drop-weight tower and test configuration described above, pointed out that the inertial load of the slabs can be considered negligible in such cases. After each impact, the mobile steel support and the slab were moved out from the drop-weight tower for checking the degradation in terms of crack propagation, crack development and crack width.…”

“…Mechanical behaviour of laminated functionally graded fibre-reinforced self-compacting cementitious composites 5 FGCC, named sometimes as CC sandwich concept [Ho et al, 2001] or hybrid concept [Grepstad & Overli, 2008;Kheder et al, 2010;Nguyen et al, 2014], some published papers dealt with the optimization of fibre quantity distribution [Shen et al, 2008;Dias et al, 2010], while others involve different concrete technologies [Bosch et al, 2006;Ma et al, 2009] but always involving a layered structure or what it is named in terms of FGM types a laminated-FGM or interface-FGM solutions which consider the gradation or FG at the interlayer levels.…”

“…In order to assess the maximum static load (P su ) of series I, series II and series III slabs, analysis of slab in failure regime can be done based on an extended yield line theory [Sánchez-Gálvez, 1999;Mosley et al, 2007;Nguyen et al, 2014]. When a square slab is subjected to a bending moment (M p ) yielded from concentrated load (P) at slab's centre, based on conservation of virtual work which prescribes the internal energy dissipation equals to the external virtual work, the ultimate static load can be derived as eight times of bending moment, which is given in Eq.…”