Fire resistance of ferrocement | |
| Author | Vatwong Greepala |
| Call Number | AIT Diss. no.ST-07-03 |
| Subject(s) | Fire resistant materials Ferrocement |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation;no. ST-07-03 |
| Abstract | The fire resistance of ferrocement jacket was evaluated by in vestigating the structural integrity and insulation property of ferroc ement specimens exposed to fire. Structural integrity is obtained by measuri ng the residual flexural strength, toughness and visible damages of ferroce ment specimen which have been exposed to fire, whereas the insulation prope rties are de- termined from thermal conductivity and specific heat of ferr ocement panels using the ANSYS finite element program. The investigation pa rameters in the experimental program are the individual composition of ferrocement, namely mortar, skeletal steel and wire mesh, the volume frac tion of wire mesh, and the mortar covering. The investigation part is div ided into four parts, namely experimental fire resistance test, thermal co nductivity test, specific heat determination, and fire resistance determinat ion. Ferrocement specimens which had dimensions of 200 mm x 240 mm x 25 mm contai ned rebars having a diameter of 6 mm spaced at 100 mm center to cent er and the mortar compressive strength was maintained at 57 MPa.For the first part, the experimental fire resistance test, a sa ndwich- sample configuration of the ferrocement specimen was adopte d to simulate the actual conditions of exposure to fire in accordance with A STM E119 in order to determine the structural integrity and experime ntal insulation property. For the second part, the thermal conductivity tes t, the thermal conductivity of ferrocement at elevated temperatures up to 1060 ◦ C was experimentally determined based on steady-state thermal p roperties mea- surement in accordance with ASTM C177. The specific heat capa city was determined from the experimental insulation property and t hermal con- ductivity results using a finite element model based on the in verse thermal analysis approach for the third part. Finally, a prediction of insulation property of ferrocement jacket exposed to standard fire was p erformed us- ing thermal conductivity and specific heat of the materials o btained from the three parts. The insulation performance of a ferrocemen t jacket was also compared with those using other materials. The experimental results showed that ferrocement jackets e xhibited bet- ter post-fire flexural strength and toughness compared with p lain mortar or concrete cover. It was also found that although an increas e in wire mesh content significantly improved the flexural strength and tou ghness of fer- rocement under normal conditions, after fire exposure the co ntent of wire mesh was no longer significant to these two mechanical proper ties. For the range of mortar coverings investigated, mortar covers had n egligible influ- ence on either the flexural strength or the toughness of ferro cement jacket under normal and after fire exposures. However more visible d amages of ferrocement jacket after exposure to fire occurred in ferroc ement with thin- ner mortar covering. It was also found that thermal conducti vity was in the range of 0.3-1.5 W/m-K. The thermal conductivity of ferr ocement wasfound to increase as temperature increased and the use of ske letal steel and wire mesh resulted in higher thermal conductivity compa red with that of plain mortar. An increase in wire mesh content decreased t he thermal conductivity of ferrocement although wire mesh is thermall y conducting. The analytical results showed that the specific heat capacit y of ferroce- ment was slightly higher than that of concrete cover given by Eurocode 2, hence it can absorb more heat than concrete cover. Compared w ith plain mortar, the incorporation of skeletal steel and wire mesh si gnificantly in- creased specific heat capacity of ferrocement. An increase i n wire mesh content resulted in slightly decreased general value of spe cific heat capacity of ferrocement; however at the second peak (600 ◦ C) an increase in vol- ume fraction of wire mesh significantly increased specific he at at the peak. For the range of mortar covering investigated, it was found t hat a mortar covering of 2.0 mm showed the highest value of specific heat ca pacity. For insulation performance using ferrocement jacket compared with using other materials, it was found that the ferrocement jacket require d a longer pe- riod to reach critical temperature than concrete cover due t o its insulation property. Both the experimental and analytical results revealed that besides be- ing used as a strengthening material ferrocement jacket is a satisfactory solution for fire protection material due to its post-fire flex ural strength, toughness, thermal conductivity and specific heat as compar ed with that of plain mortar or concrete cover. |
| Year | 2007 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation;no. ST-07-03 |
| Type | Dissertation |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pichai Nimityongskul; |
| Examination Committee(s) | Worsak Kanok-Nukulchai ;Park, Kyung-Ho; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (Ph.D) - Asian Institute of Technology, 2007 |