A novel lightweight cement composite incorporating micro-sized silica aerogel / Syed Nasir Shah
Lightweight cement composite (LCC) has gained more interest and is increasingly explored by researchers due to its many advantageous properties. Silica aerogel (SA), a synthetic ultralightweight material with a nano-porous structure and remarkable insulation properties, makes it a potential optio...
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2022
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| Online Access: | http://studentsrepo.um.edu.my/15522/1/Syed_Nasir_Shah.pdf http://studentsrepo.um.edu.my/15522/2/Syed_Nasir_Shah.pdf http://studentsrepo.um.edu.my/15522/ |
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| _version_ | 1831436648180613120 |
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| author | Syed Nasir , Shah |
| author_facet | Syed Nasir , Shah |
| author_sort | Syed Nasir , Shah |
| building | UM Library |
| collection | Institutional Repository |
| content_provider | Universiti Malaya |
| content_source | UM Student Repository |
| continent | Asia |
| country | Malaysia |
| description | Lightweight cement composite (LCC) has gained more interest and is increasingly
explored by researchers due to its many advantageous properties. Silica aerogel (SA), a
synthetic ultralightweight material with a nano-porous structure and remarkable
insulation properties, makes it a potential option to be incorporated in LCC. LCC
incorporating SA (SA-LCC) would be an ideal insulating building material and could
promote energy efficiency in buildings since the building sector consumes about 30-40%
of global energy consumption. However, there are some challenges when it comes to
incorporating SA into LCC. One of the difficulties is mixing SA with cement composite
due to its ultra-lightweight and hydrophobic nature. Thus, this research aims to develop
a chemical treatment for SA to ease its mixing and assess the influence of micro-sized SA
on the properties of LCC. Therefore, a detailed study was conducted on both untreated
and treated SA-LCC. The study was divided into 3 phases; where phase 1 focuses on
developing chemical treatment for SA, characterizing untreated and treated SA, and
evaluating the effect of different content of untreated/treated SA (20-80% of sand
replacement) on the basic properties of LCC. The results of phase 1 revealed that the
treated SA became temporarily hydrophilic and eased the mixing. In addition, the
chemical treatment did not affect the pore structure, particle size distribution, chemical
bonds, and crystallographic structure of SA. A significant reduction in the oven-dry
density (up to 50%) and compressive strength (up to 80%) of SA-LCC was observed,
while the porosity was increased (up to 260%). Phase 2 emphasizes the insulating
properties, dimensional stability, durability performance, and microstructure
characteristics of SA-LCC. Despite the increase in water absorption (140/290%) and
decrease in water resistance (11/19%), the increase in porosity of LCC due to
incorporation of untreated/treated SA improved the insulating properties. The noise reduction coefficient (NRC) improved up to 15%, whereas the thermal conductivity was
improved up to 80%. Despite the beneficial insulating properties, the limitations of the
SA-LCC include the higher shrinkage (10 times) and lower resistance to elevated
temperatures, in addition to increased water absorption. Nevertheless, in overall, LCC
with a low oven-dry density of about 1190 kg/m3 and adequate compressive strength (6.38
MPa) can be produced by incorporating treated SA, which has a low thermal conductivity
(0.220 W/m.K) and good NRC (0.261). Therefore, in phase 3, in view of the observed
limitations of the SA-LCC, a scaled lightweight sandwich wall panel (SWP) was
introduced, which utilized calcium silicate board (CSB) as the skin. This is intended for
wall application to suit the benefits of the SA-LCC. The practical application of treated
SA-LCC as core for SWP shows that non-load bearing SWP can be produced with treated
SA-LCC and 6 mm CSB as the skin with unit weight, compressive, and flexural strength
of 1570 kg/m3, 2.4 MPa, and 4.7 MPa, respectively. The SWP also has good impact load
resistance (70 J) and direct flame resistance. Furthermore, the SWP has satisfactory
insulating properties with NRC and thermal conductivity of 0.259 and 0.561 W/m.K,
respectively.
|
| format | Thesis |
| id | my.um.stud-15522 |
| institution | Universiti Malaya |
| publishDate | 2022 |
| record_format | eprints |
| spelling | my.um.stud-155222025-02-09T20:43:59Z A novel lightweight cement composite incorporating micro-sized silica aerogel / Syed Nasir Shah Syed Nasir , Shah TA Engineering (General). Civil engineering (General) Lightweight cement composite (LCC) has gained more interest and is increasingly explored by researchers due to its many advantageous properties. Silica aerogel (SA), a synthetic ultralightweight material with a nano-porous structure and remarkable insulation properties, makes it a potential option to be incorporated in LCC. LCC incorporating SA (SA-LCC) would be an ideal insulating building material and could promote energy efficiency in buildings since the building sector consumes about 30-40% of global energy consumption. However, there are some challenges when it comes to incorporating SA into LCC. One of the difficulties is mixing SA with cement composite due to its ultra-lightweight and hydrophobic nature. Thus, this research aims to develop a chemical treatment for SA to ease its mixing and assess the influence of micro-sized SA on the properties of LCC. Therefore, a detailed study was conducted on both untreated and treated SA-LCC. The study was divided into 3 phases; where phase 1 focuses on developing chemical treatment for SA, characterizing untreated and treated SA, and evaluating the effect of different content of untreated/treated SA (20-80% of sand replacement) on the basic properties of LCC. The results of phase 1 revealed that the treated SA became temporarily hydrophilic and eased the mixing. In addition, the chemical treatment did not affect the pore structure, particle size distribution, chemical bonds, and crystallographic structure of SA. A significant reduction in the oven-dry density (up to 50%) and compressive strength (up to 80%) of SA-LCC was observed, while the porosity was increased (up to 260%). Phase 2 emphasizes the insulating properties, dimensional stability, durability performance, and microstructure characteristics of SA-LCC. Despite the increase in water absorption (140/290%) and decrease in water resistance (11/19%), the increase in porosity of LCC due to incorporation of untreated/treated SA improved the insulating properties. The noise reduction coefficient (NRC) improved up to 15%, whereas the thermal conductivity was improved up to 80%. Despite the beneficial insulating properties, the limitations of the SA-LCC include the higher shrinkage (10 times) and lower resistance to elevated temperatures, in addition to increased water absorption. Nevertheless, in overall, LCC with a low oven-dry density of about 1190 kg/m3 and adequate compressive strength (6.38 MPa) can be produced by incorporating treated SA, which has a low thermal conductivity (0.220 W/m.K) and good NRC (0.261). Therefore, in phase 3, in view of the observed limitations of the SA-LCC, a scaled lightweight sandwich wall panel (SWP) was introduced, which utilized calcium silicate board (CSB) as the skin. This is intended for wall application to suit the benefits of the SA-LCC. The practical application of treated SA-LCC as core for SWP shows that non-load bearing SWP can be produced with treated SA-LCC and 6 mm CSB as the skin with unit weight, compressive, and flexural strength of 1570 kg/m3, 2.4 MPa, and 4.7 MPa, respectively. The SWP also has good impact load resistance (70 J) and direct flame resistance. Furthermore, the SWP has satisfactory insulating properties with NRC and thermal conductivity of 0.259 and 0.561 W/m.K, respectively. 2022-05 Thesis NonPeerReviewed application/pdf http://studentsrepo.um.edu.my/15522/1/Syed_Nasir_Shah.pdf application/pdf http://studentsrepo.um.edu.my/15522/2/Syed_Nasir_Shah.pdf Syed Nasir , Shah (2022) A novel lightweight cement composite incorporating micro-sized silica aerogel / Syed Nasir Shah. PhD thesis, Universiti Malaya. http://studentsrepo.um.edu.my/15522/ |
| spellingShingle | TA Engineering (General). Civil engineering (General) Syed Nasir , Shah A novel lightweight cement composite incorporating micro-sized silica aerogel / Syed Nasir Shah |
| title | A novel lightweight cement composite incorporating micro-sized silica aerogel / Syed Nasir Shah |
| title_full | A novel lightweight cement composite incorporating micro-sized silica aerogel / Syed Nasir Shah |
| title_fullStr | A novel lightweight cement composite incorporating micro-sized silica aerogel / Syed Nasir Shah |
| title_full_unstemmed | A novel lightweight cement composite incorporating micro-sized silica aerogel / Syed Nasir Shah |
| title_short | A novel lightweight cement composite incorporating micro-sized silica aerogel / Syed Nasir Shah |
| title_sort | novel lightweight cement composite incorporating micro-sized silica aerogel / syed nasir shah |
| topic | TA Engineering (General). Civil engineering (General) |
| url | http://studentsrepo.um.edu.my/15522/1/Syed_Nasir_Shah.pdf http://studentsrepo.um.edu.my/15522/2/Syed_Nasir_Shah.pdf http://studentsrepo.um.edu.my/15522/ |
| url_provider | http://studentsrepo.um.edu.my/ |