Based on vapor pressure spalling theory, the vapor pressure in self consolidating concrete(SCC) and fiber reinforced self consolidating concrete(FRSCC) was predicted using the one dimensional model of multi phase porous media. Vapor pressure induced spalling behavior of SCC and FRSCC was analyzed. In order to verify the validity of the proposed model, vapor pressure tests for SCC and FRSCC under fire were performed. Effects of steel fiber, micro polypropylene(PP) fiber, macro PP fiber and hybrid fiber on the relationship of vapor pressure time temperature were discussed. The results indicated that the addition of fibers can decrease the vapor pressure in SCC, delay the occurrence time of the peak value of pore pressure and can decrease the corresponding temperature at peak pressure. The pore pressure can be reduced by using micro PP fibers more effectively than by macro PP fibers. The significant factor for reduction of vapor pressure depends mainly on the number of PP fibers as well as on the fiber content. Compared to mono fiber, the use of hybrid fibers can further reduce the vapor pressure in SCC. Through comparison with the test results, it is found that the simulation model presented can well predict the build up of vapor pressure and fire spalling behavior of SCC and FRSCC.
PENG Gaifei,YANG Juan,SHI Yunxing,et al.Explosive spalling resistance of ultrahigh performance concrete[J].Journal of Building Materials,2017,20(2):229 233.(in Chinese)
[3]EZZIANE M,MOLEZ L,JAUBERTHIE R.Heat exposure tests on various types of fibre mortar[J].European Journal of Environmental and Civil Engineering,2011,15(5):715 726.
[4]BANGI M R,HORIGUCHI T.Pore pressure development in hybrid fibre reinforced high strength concrete at elevated temperatures[J].Cement and Concrete Research,2011,41:1150 1156.
[5]BANGI M R,HORIGUCHI T.Effect of fiber type and geometry on maximum pore pressures in fiber reinforced high strength concrete at elevated temperatures[J].Cement and Concrete Research,2012,42:459 466.
[6]BOSNJAK J,OZBOLT J,HAHN R.Permeability measurement on high strength concrete without and with polypropylene fibers at elevated temperatures using a new test setup[J].Cement and Concrete Research,2013,53:104 111.
LIU Genjin,DING Yining.Effect of fibers on deformation behavior of concrete pipe at high temperature[J].Journal of Building Materials,2018,21(5):786 790.(in Chinese)
[8]TOROPOVS N.Real time measurements of temperature,pressure and moisture profiles in high performance concrete exposed to high temperature during neutron radiography imaging[J].Cement and Concrete Research,2015,68:166 173.
[9]FELICETTI R,MONTE F L,PIMIENTA P.A new test method to study the influence of pore pressure on fracture behaviour of concrete during heating[J].Cement and Concrete Research,2017,94:13 23.
[10]MONTE F L,FELICETTI R.Heated slabs under biaxial compressive loading:A test set up for the assessment of concrete sensitivity to spalling[J].Materials and Structures,2017,50:192.
[11]MINDEGUIA J C,PIMIENTA P,CARRE H.Experimental analysis of concrete spalling due to fire exposure[J].European Journal of Environmental and Civil Engineering,2013,17(6):453 466.
[12]MITSUO O.Study of mechanisms of explosive spalling in high strength concrete at high temperatures using acoustic emission[J].Construction and Building Materials,2012,37:621 628.
[13]PHAN L T.Pore pressure and explosive spalling in concrete[J].Materials and Structures,2008,41:1623 1632.
[14]ROBERT J,LARS B.The influence of pressure in the pore system on fire spalling of concrete[J].Fire Technology,2010,46:217 230.
[15]DING Y N,ZHANG C,CAO M L.Influence of different fibers on the change of pore pressure of self consolidating concrete exposed to fire[J].Construction and Building Materials,2016,113:456 469.
[16]GAWIN D,PESAVENTO F,SCHREFLER B A.Modelling damage processes of concrete at high temperature with thermodynamics of multi phase porous media[J].Journal of Theoretical and Applied Mechanics,2006,44(3):502 532.
[17]GAWIN D,PESAVENTO F,SCHREFLER B A.Towards prediction of the thermal spalling risk through a multi phase porous media model of concrete[J].Computer Methods in Applied Mechanics and Engineering,2006,195:5707 5729.
[18]GAWIN D,PESAVENTO F,SCHREFLER B A.What physical phenomena can be neglected when modelling concrete at high temperature? A comparative study.Part 1:Physical phenomena and mathematical model[J].International Journal of Solids and Structures,2011,48:1927 1944.
[19]GAWIN D,PESAVENTO F,SCHREFLER B A.What physical phenomena can be neglected when modelling concrete at high temperature? A comparative study.Part 2:Comparison between models[J].International Journal of Solids and Structures,2011,48:1945 1961.
[20]GAWIN D,PESAVENTO F.An overview of modeling cement based materials at elevated temperatures with mechanics of multi phase porous media[J].Fire Technology,2012,48:753 793.
[21]ICHIKAWA Y,ENGLAND G L.Prediction of moisture migration and pore pressure build up in concrete at high temperatures[J].Nuclear Engineering and Design,2004,228:245 259.
[22]CHUNG J H,CONSOLAZIO G R.Numerical modeling of transport phenomena in reinforced concrete exposed to elevated temperatures[J].Cement and Concrete Research,2005,35（3）:597 608.
[23]TENCHEV R,PURNELL P.An application of a damage constitutive model to concrete at high temperature and prediction of spalling[J].International Journal of Solids and Structures,2005,42:6550 6565.
[24]ZEIML M,LACKNER R,PESAVENTO F.Thermo hydro chemical couplings considered in safety assessment of shallow tunnels subjected to fire load[J].Fire Safety Journal,2008,43:83 98.
[25]MINDEGUIA J C,PIMIENTA P,NOUMOWE A.Temperature,pore pressure and mass variation of concrete subjected to high temperature Experimental and numerical discussion on spalling risk[J].Cement and Concrete Research,2010,40(3):477 487.
[26]DAVIE C T,ZHANG H L,GIBSON A.Investigation of a continuum damage model as an indicator for the prediction of spalling in fire exposed concrete[J].Computers and Structures,2012,95:54 69.
[27]ZHANG H L,DAVIE C T.A numerical investigation of the influence of pore pressures and thermally induced stresses for spalling of concrete exposed to elevated temperatures[J].Fire Safety Journal,2013,59:102 110.
[28]TRABELSI A,HAMANI A,BELARBI R.Assessment of the variability of moisture transfer properties of high performance concrete from a multi stage drying experiment[J].European Journal of Environmental and Civil Engineering,2012,16(3 4):352 361.
[29]ALBERT N,RAFAT S,DEBICKI G.Permeability of high performance concrete subjected to elevated temperature(600℃)[J].Construction and Building Materials,2009,23(5):1855 1861.
[30]POWERS T C.Structure and physical properties of hardened Portland cement paste[J].Journal of the American Ceramic Society,1958,41(1):1 6.
[31]ATLASSI E H.Nonevaporable water and degree of cement hydration in silica fume cement systems[J].ACI Special Publication,1995,153:703 718.
[32]MILLS R.Factors influencing cessation of hydration in water cured cement pastes[J].Highway Research Board Special Report,1966(90):406 424.
[33]SENGERS J.Improved international formulations for the viscosity and thermal conductivity of water substance[J].Journal of Physical and Chemical Reference Data,1986,15(4):1291 1314.
[34]MITSUO O,SHINYA U,TOSHIRO K.Study of mechanisms of explosive spalling in high strength concrete at high temperatures using acoustic emission[J].Construction and Building Materials,2012,37:621 628.
[35]SAUL A,WAGNER W.International equations for the saturation properties of ordinary water substance[J].Journal of Physical and Chemical Reference Data,1987,16(4):893 901.
[36]SAUL A,WAGNER W.A fundamental equation for water covering the range from the melting line to 1273 K at pressures up to 25000MPa[J].Journal of Physical and Chemical Reference Data,1989,18(4):1537 1564.
[37]PARROTT L.Moisture profiles in drying concrete[J].Advances in Cement Research,1988,1(3):164 170.
[38]JIANG J,YUAN Y.Relationship of moisture content with temperature and relative humidity in concrete[J].Magazine of Concrete Research,2013,65(11):685 692.
[39]LI Y,TAN K H,YANG E H.Influence of aggregate size and inclusion of polypropylene and steel fibers on the hot permeability of ultra high performance concrete(UHPC) at elevated temperature[J].Construction and Building Materials,2018,169:629 637.
