Properties Of Cement Syntactic Foam Composite For Sound Insulation Application

Hasan, Norwanis (2018) Properties Of Cement Syntactic Foam Composite For Sound Insulation Application. PhD thesis, Universiti Sains Malaysia.

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An innovative technique, in producing Cement Syntactic Foam (CSF) composite, is proposed in this research project. This cellular composite material consists of a cement matrix embedded with in-house developed Cement Hollow macrosphere (CHS). Simple and innovative approach was implemented in the preparation of CHS where expanded polystyrene (EPS) beads were used as initiation material to generate the hollow sphere. The EPS beads were coated with the epoxy resin and cement powder, were later cured and post-cured at high temperature. This process shrinks the EPS beads thus producing a hollow sphere structure. The CHSs were coated for second and triple coating as to vary the wall thicknesses. The CSF composites produced by CHS with single, double and triple coatings are referred as CSF-1x, CSF-2x and CSF-3x, respectively. The process of pre-determined amount of CHS before fabricating the CSF composite, gave an optimal packing of sphere as to achieve well distributed void. This step successfully reduced the density of CSF-1x, CSF-2x and CSF-3x, almost 51%, 47% and 41% respectively in comparison to the control plain cement (PC). The compressive strengths of CSF-1x, CSF-2x and CSF-3x were 8.9, 11.7 and 13.3 MPa, respectively. From the comparative compressive properties of CSFs it were found that the CSF incorporated with thicker-coatings of CHS showed a higher compressive strength than that incorporated with thinner-coatings of CHS. The failure patterns within the test samples are examined to determine the failure mechanism. These observations show that both CSFs exhibited shearing type failures, but with different types of crack fractures caused by differences in CHS wall thicknesses. Acoustic tests (sound absorption and sound transmission loss) were conducted to examine the acoustic behaviour of CSF in comparison to PC. The sound absorption coefficient in CSF at frequencies of 400 Hz to 1600 Hz was in the range of 0.15 to 0.25, whereas the PC was below 0.15. The significant improvement of sound absorption in CSF over PC can be attributed to the presence of open porosity combined with rough internal pores on its surface. This rough and porous structure allows considerable sound wave dissipation via friction when in contact with the CSF surface sample; thus raising the sound absorption coefficient. The sound transmission loss in CSF at frequencies of 400 Hz to 1600 Hz was in the range 20 to 60 dB; whereas the PC was in the range 60 to 80 dB. The closed-cell structure of the CSF prevented the passage of air, thus giving high resistance to the sound wave’s travel as similarly experience by PC. The simulation study was successfully performed using ANSYS-FLUENT 14 software. From the simulation, it was found that the interaction between the properties of the material and sound pressure can be visualized; which usually is difficult to achieve in a laboratory setting.

Item Type: Thesis (PhD)
Subjects: T Technology
T Technology > TN Mining Engineering. Metallurgy
Divisions: Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Bahan & Sumber Mineral (School of Material & Mineral Resource Engineering) > Thesis
Depositing User: Mr Engku Shahidil Engku Ab Rahman
Date Deposited: 21 Dec 2022 07:55
Last Modified: 21 Dec 2022 07:55

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