30 4A 2010 7 391

30 4A2010 7

pp. 391 ~ 398

RC

Evaluation of Fire Performance of RC Slabs with Half-Depth Precast Panels

**********

Chung, Chul-HunIm, Cho-RongKim, Hyun-JunJoo, Sang-Hoon

Abstract

The fire performance of RC slabs with half-depth precast panel after exposure to the ISO-834 fire standard without loading

has been experimentally investigated. During heating, according to the ISO 834 fire curve, concrete spalling was observed for

concrete without PP(polypropylene) fibers. No spalling occurred when heating concrete containing PP fibers. The maximum

temperature of RC slabs with PP fibers with half-depth precast panel was lower than that of concrete without PP fibers. The

ultimate load after cooling of the RC slabs that were not loaded during the furnace tests was evaluated by means of 3 points

bending tests. The ultimate load of the RC slabs without PP fibers showed a considerable reduction (around 32.5%) of the ulti-

mate load after cooling if compared with of RC slabs with PP fibers. The ultimate load of the RC slabs with half-depth precast

panel with PP fibers is higher than that of a full-depth RC slabs with PP fibers. Also, the addition of PP fibers and the use of

half-depth precast panel improve fire resistance.

Keywords : fire performance, PP(polypropylene) fiber, explosive spalling, fire curve, half-depth precast panel, ultimate load

RC ISO-834

. PP , PP

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3 . , PP RC PP 32.5%

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1.

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(Ali, 1992; , 2009).

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1995; Atkinson, 2004) (Purkiss, 1984; Lie ,

1996; Suhaendi , 2006)

. (2007)

, .

* (E-mail : chchung5@dankook.ac.kr)

** (E-mail : dlachfhd@dankook.ac.kr)

*** (E-mail : rolandgarros@hanmail.net)

****() (E-mail : smeared@paran.com)

392

Poon (2004) (2009)

,

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2008) ,

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30 4A 2010 7 393

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20, 50(), 100

( : 90 mm), 150(), 180 mm

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(1)

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To : (20oC)

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180 .

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. (a) ,

20 mm

,

150 mm

. PP 0.10 vol.%

T t( ) 345 8t 1+( ) To

+=

2. PP

Polypropylene fibers

(g/cm3) 0.91

(m) 21.6~39.4

(mm) 5~10

(MPa) 328.3~367.7

(GPa) 3.0~3.2

3. (kg/m3)

W/C(%) S/a(%) Water Cement Sand Gravel Admixture PP fibers

38.5 38.9 170 442 692 1113 3.49 0.45~1.82

5. ISO 834

6.

30 4A 2010 7 395

20 mm

, 150 mm

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: 0, 0.10 vol.%)

(PP 0.10 vol.%)

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(350.4 kN) PP

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(316.9 kN) 80% . PP

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100 mm

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30 4A 2010 7 397

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kN . PP

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0.10 vol.%

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2

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----------- 3+

-------------------------------------------=

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(vol.%)

(kNm)

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(kN)

(mm) /

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0.90437.89

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0.10 350.4

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350.6 43.92

398

. , PP

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RC

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1. ISO 834 3 ,

PP

100 mm PP

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PP

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, 100 mm

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PP RC

PP RC

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32.5% , PP

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111%

. ,

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-

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PP

PP

,

.

, , , (2007) Fiber Cocktail

, ,

, pp. 605-608.

, , (2009)

, ,

, Vol. 21, No. 4, pp. 465-471.

(2005) -

KS F 2257-7, .Abrams, M.S. (1971) Compressive strength of concrete at tempera-

tures to 1600F, Temperature and Concrete, SP-25, American

Concrete Institute, Detroit, pp. 33-58.

ACI Committee 216 (1989) Guide for Determining the Fire Endur-

ance of Concrete Elements, ACI 216R-89, American Concrete

Institute, Detroit.

Ali, F. (2002) Is high strength concrete more susceptible to explo-

sive spalling than normal strength concrete in fire, Fire and

Materials, Vol. 26, pp. 127-130.

Atkinson, T. (2004) Polypropylene fibers control explosive spalling

in high-performance concrete, Concrete, Vol. 38, No. 10, pp.

69-70.

EUROCODE 2 (2004) Design of Concrete Structures-Part 1.2:

General rules- Stuructural Fire Design, Brussels, July.

ISO (1975) Fire Resistance Tests-Elements of Building Construc-

tion, International Standard ISO 834, Geneva.

Lie, T.T. and Kodur, V.K.R. (1996) Thermal and mechanical properties

of steel-fibre-reinforced concrete at elevated temperatures, Cana-

dian Journal of Civil Engineering, Vol. 23, pp. 511-517.

Nishida, A., Ymazaki, N., Inoue, H., Schneider, U., and Dieder-

ichs, U. (1995) Study on the properties of high-strength con-

crete with short polypropylene fibre for spalling resistance,

Proceedings of International Conference on Concrete under

Severe Conditions, CONSEC'95, Vol. 2, Sapporo, Japan, pp.

1141-1150.

Poon, C.S., Shui, Z.H., and Lam, L. (2004) Compressive behavior

of fiber reinforced high-performance concrete subjected to ele-

vated temperatures, Cement and Concrete Research, Vol. 34,

No. 12, pp. 2215-2222.

Purkiss, J.A. (1984) Steel fibre reinforced concrete at elevated tem-

peratures, International Journal of Cement Composites and

Lightweight Concrete, Vol. 6, No. 3, pp. 179-184.

Suhaendi, S.L. and Horiguchi, T. (2006) Effect of short fibers on

residual permeability and mechanical properties of hybrid fibre

reinforced high strength concrete after heat eposition, Cement

and Concrete Research, Vol. 36, pp. 1672-1678.

Yang, H., Han, L.H., and Wang, Y.H. (2008) Effects of heating

loading histories on post-fire cooling behaviour of concrete-

filled steel tubular columns, Journal of Constructional Steel

Research, Vol. 64, pp. 556-570.

(: 2010.2.11/: 2010.3.19/: 2010.5.5)