Pore pressure development in hybrid fibre-reinforced high strength concrete at elevated temperatures

Abstract

The present experimental work investigates the build -up of pore pressure at different depths of High Strength Concrete (HSC) and Hybrid-Fibre-Reinforced High Strength Concrete (HFRHSC) when exposed to different heating rates. First, the effect of the measurement technique on maximum pore pressures measured was evaluated. The pressure measurement technique which utilized a sintered metal and silicon oil was found to be the most effective technique for pore pressure measurement. Pore pressure measurements carried out showed that addition of polypropylene fibres is very effective in mitigation of spalling and build -up of pore pressure inside heated HSC. Addition of steel fibres plays some role in pore pressure reduction at relatively higher pressures in deeper regions of concrete during fast heating. Pore pressure development is highly influenced by the rate of heating with fast heating leading to higher pore pressures in the deeper regions of concrete compared to slow heating.

Strength, permeability, and durability of hybrid fiber‐reinforced concrete containing styrene butadiene latex

“…Therefore, blending two or more types of fibers (“hybrid fiber”) has been investigated in an attempt to improve the concrete properties 5, 6. Hybrid fiber systems aim to provide a composite with superior properties by capitalizing on the merits of each fiber type 7–9. Hybrid fiber‐reinforced concrete (HFRC) uses fibers having different physical and mechanical properties to suppress cracking and improve the mechanical performance and durability 10, 11.…”

Experimental discussion on the mechanisms behind the fire spalling of concrete

“…Just prior to tests, type K thermocouples (diameter 1.5 mm) are put in these tubes. It is worth noting that the free volume between the tube and the thermocouple (130 mm 3 ) were not filled with any sort of fluid, which can be different than other similar studies [9,17]. The gas pressure in concrete is first transmitted via the metallic tubes to an external 'T-junction', and then to an external pressure transducer (piezo-electrical transducer) via plastic tubes filled with silicon oil.…”

An experimental investigation into the influence of specimen size, in-situ pore pressures and temperatures on the spalling of difference size concrete panels when exposed to a hydrocarbon fire

“…The measurements were taken at 25, 50, 75, 100 and 150 from the heated face. The setup used for the pore pressure measurements is in alignment with the works of [9][10][11] which describes the procedure in detail. Essentially, a pipe of length 300 mm and inside diameter of 5 mm is located at the measurement point and extends out on the non exposed side of the concrete panel.…”