The Basic Mechaniccal Properties Of HFRC And Anti-blasting Performance Of HFRC Plate

As a multiphase material,micro-cracking exists in concrete before applying loads,it will help the concrete to improve the defects by addingthe fibre.Compared to the single fibre,different quality and different geometry of fibre mixed with concretecan improve fibre distribution balance from different levels,increase efficiency.This paper means to test the basic mechanical properties and anti-blasting performance of concrete mixed with steel-PVA fibre or steel-basalt fibre.It tends to explore the influence of different fibre ratio on concrete performance by the cube compressive strength test,splitting tensile test,flexural toughness test and hybrid fibre reinforced concrete plate’s surface contact explosion test.The proportion of all 12 groups takes by 3 dosage of steel fibre volume ratio:0.5%,1%,2%,3 dosage of PVA fibre volume ratio:0.05%,0.1%,0.15%,1 basalt fibre content volume ratio:0.1%.Conclusion as follows:(1)The fibres have little impact on compressive strength.The HFRC is multiple-cracking in compression.The steel fibre plays the major role on compression.In large dosage of steel fibre(2%),the compressive strength increases by about 20%.The compressive strength of concrete will be relatively reduced as steel fibre ratio is low(0.5%～1%).Basalt fibre is barely effective on the compressive strength of hybrid fibre.(2)Hybrid fibre can improve the tensile strength of concrete,by about 23%～103%.Steel fibre play dominant role on improving the tensile strength of hybrid fibre concrete.In low dosage of steel fibre(0.5%),the tensile strength of hybrid fibre reinforced concrete can also be increased by 20%at least.(3)Hybrid fibre can raise the early crack strength,ultimate flexural loading and flexural toughness of the concrete.The most obvious is that,flexural toughness can be increased by 6～15 times with hybrid fibres in concrete.With the increase of steel fibre ratio,flexural toughness will increase;as the ratio of PVA fibre increasing,flexural toughness increase after decreases first in a certain range.Basalt fibre performance is not better than or worse than PVA fibre.(4)The hybrid fibres in concretediminish the brittleness of concrete result in tension-compressive strength improvement.Since the ratios of steel fibre and PVA fibre are growing,it appears that tension-compressive strength raise on.As the ratio of steel fibre is 1%or2%,the steel-basalt hybridfibre reinforced concrete’s tension-compression ratio is similar.(5)The anti-blasting ability of hybrid fibre reinforced concrete plate is better than common reinforced concrete plates’,particularly express on the backside’s spalling.As short fibre ratio is low(0.05%PVA fibre or BF0.1%),increasing the dosage of steel fibre can strengthenhybrid fibre reinforced concrete plate’s anti-blasting ability effectively in the low steel fibre ratio section(<1%).However,as the short fibre ratio is high(0.1%～0.15%PVA fibre),increasing the dosage of steel fibre is more obvious to enhance hybrid fibre reinforced concrete plate’s anti-blasting ability in the steel fibre high ratio area(>1%).