The aim of this work was to verify the influence of expandable graphite (EG) and aluminum hydroxide (ATH) fillers on the flammability of polyisocyanurate-polyurethane (PIR). Limited oxygen index increased to 72.5 with an incorporation of 16 phr (parts per hundred of matrix) EG and 50 phr ATH into the matrix (total weight percent was 39.76%). Cone calorimetry was employed to study the flammability properties of these PIR/ATH/EG composites. Scanning electron microscopy analysis was conducted to study the char characteristics of the composites after the cone calorimetry tests. It was found ATH could effectively induce villi like particles, which made the intumescent char denser, on the surface of EG. The compact char layer could effectively impede the transport of bubbles and heat. ATH and EG accelerated the initial degradation and fluffy char was quickly generated on the surface. Thus, degradation products of the composite were slowed down and the diffusion of volatile combustible fragments to flame zone was delayed.

Workability, strength and fracture mechanics of polypropylene macro-fiber reinforced Reactive powder concrete (RPC) were studied in this work. The results showed that the incorporation of macro-fiber could influence the workability of RPC, the slump of RPC decreased with the increasing of macro-fiber content; compressive strength decreased while splitting strength increased with the increasing of macro-fiber, meanwhile the flexural strength invariant. Macro-fiber could strongly enhance the flexural toughness of RPC and changed the failure mode from brittle to ductile; fracture energy tends to increase linearly with the increasing of macro-fiber.