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Fukt- och temperaturrörelser i fasad- och vindskyddsskivor

Jönsson, Anton LU and Remnetorp, Daniel LU (2019) In LUTVDG/TVBM VBMM01 20191
Division of Building Materials
Abstract (Swedish)
Användningen av fasad- och vindskyddsskivor i ytterväggskonstruktioner är i dag utbredd. Skivorna är monterade långt ut i ytterväggen och utsätts således för variationer i omgivande relativ fuktighet och temperatur. På senare tid har skador såsom buktning av skivorna och sprickbildning hos skivorna uppmärksammats. Skadorna kan bero på rörelserna hos skivorna och det är således av intresse att undersöka rörelser som beror av förändrad relativ fuktighet och temperatur.

Huvudsyftet med det här examensarbetet är att experimentellt utvärdera fukt- och temperaturrörelser för olika skivor. Skivorna som studerades var fyra fibercementskivor, en cementspånskiva, en gipsskiva och en kalciumsilikatskiva.

Grundläggande teori kring fukt och... (More)
Användningen av fasad- och vindskyddsskivor i ytterväggskonstruktioner är i dag utbredd. Skivorna är monterade långt ut i ytterväggen och utsätts således för variationer i omgivande relativ fuktighet och temperatur. På senare tid har skador såsom buktning av skivorna och sprickbildning hos skivorna uppmärksammats. Skadorna kan bero på rörelserna hos skivorna och det är således av intresse att undersöka rörelser som beror av förändrad relativ fuktighet och temperatur.

Huvudsyftet med det här examensarbetet är att experimentellt utvärdera fukt- och temperaturrörelser för olika skivor. Skivorna som studerades var fyra fibercementskivor, en cementspånskiva, en gipsskiva och en kalciumsilikatskiva.

Grundläggande teori kring fukt och värme beskrivs genom att sammanställa relevant litteratur. Längdförändringarna utvärderades experimentellt genom att placera provkroppar från skivorna i olika genererade klimat. Olika relativa fuktigheter genererades med hjälp av klimatboxar och olika temperaturer genererades med hjälp av ugnar.

Resultatet innefattar sorptionsisotermer för alla skivor. Resultatet innefattar även erhållna fuktbetingade rörelser mellan 0 %, 33 %, 95 % och 100 % relativ fuktighet, under både absorption och desorption. Temperaturbetingade rörelser mellan 20 °C och 105 °C inkluderas även i resultatet.

Cementspånskivan uppvisar generellt de största fuktbetingade rörelserna och gipsskivan uppvisar bland de minsta fuktbetingade rörelserna. För merparten av skivorna är krympningen betydligt större än svällningen. De fuktbetingade rörelserna är generellt stora mellan 0 % och 33 % relativ fuktighet samt mellan 95 % och 100 % relativ fuktighet. De temperaturbetingade rörelserna uppmätts som störst för gipsskivan följt av fibercementskivorna och cementspånskivan. Kalciumsilikatskivan uppvisar de minsta temperaturbetingade rörelserna.

Vilken av de fukt- eller temperaturbetingade rörelserna som är störst skiljer sig mycket mellan olika skivor och beror på vilket intervall av relativ fuktighet och temperatur skivan exponeras för. För cementspånskivan är de fuktbetingade rörelserna betydligt större än de temperaturbetingade. För gipsskivan är de fuktbetingade rörelserna betydligt mindre än de temperaturbetingade. (Less)
Abstract
The use of boards as facades and sheathing is today common practice. Facade and sheathing boards are located far out in the building envelope and are thus subjected to variations of the surrounding relative humidity and temperature. Recently different kinds of damage on the boards have been brought to attention. The damage is varying and include cracking or warping of the boards. The damage may depend on moisture and thermal induced movement in the boards and it is therefore of interest to study these movements.

The main purpose of this master's thesis is to evaluate the magnitude of moisture and thermal induced movement for different boards. The boards include four fibre cement boards, one cement particle board, one gypsum board and... (More)
The use of boards as facades and sheathing is today common practice. Facade and sheathing boards are located far out in the building envelope and are thus subjected to variations of the surrounding relative humidity and temperature. Recently different kinds of damage on the boards have been brought to attention. The damage is varying and include cracking or warping of the boards. The damage may depend on moisture and thermal induced movement in the boards and it is therefore of interest to study these movements.

The main purpose of this master's thesis is to evaluate the magnitude of moisture and thermal induced movement for different boards. The boards include four fibre cement boards, one cement particle board, one gypsum board and one calcium silicate board.

Essential theory of moisture and heat is presented using relevant literature. The moisture and thermal induced movements were obtained by placing samples of the boards in different generated climates. Different relative humidities were generated using climate boxes and different temperatures were generated using ovens. Moisture and thermal induced movements and also sorption isotherms were evaluated for all boards.

The result includes sorption isotherms of all boards. The result also includes the moisture induced movements between 0 %, 33 %, 95 % and 100 % relative humidity, during both absorption and desorption. The thermal induced movements between 20 °C and 105 °C are also included in the result.

The results show that the moisture induced movements of the boards generally are the largest for the cement particle board. The gypsum board has one of the smallest moisture induced movements. Most boards exhibit considerably larger shrinkage than swelling. The moisture induced movements are generally large between 0 % to 33 % relative humidity and between 95 % to 100 % relative humidity. The thermal induced movements are the largest for the gypsum board, followed by the fibre cement boards and the cement particle board. The calcium silicate board exhibits the smallest thermal induced movements.

Which of the moisture or thermal induced movements that is the largest differ a lot between the boards and depend on which interval of temperature and relative humidity the board is exposed to. The moisture induced movements are considerably larger than the thermal induced movements for the cement particle board. The gypsum board shows considerably larger thermal than moisture induced movements. (Less)
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author
Jönsson, Anton LU and Remnetorp, Daniel LU
supervisor
organization
course
VBMM01 20191
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Fibercementskiva, cementbunden fiberskiva, oorganisk kompositgipsskiva, gipsskiva, kalciumsilikatskiva, cementspånskiva, längdutvidgningskoefficient, krympning, svällning, töjning, sorption, sorptionsisoterm, relativ fuktighet, klimatbox Fibre cement board, cement particle board, inorganic composite gypsum board, calcium silicate board, coefficient of thermal expansion, swelling, shrinkage, strain, isotherm, moisture content, relative humidity, climate box
publication/series
LUTVDG/TVBM
report number
5117
other publication id
LUTVDG/TVBM-19/5117-SE
language
Swedish
id
8982905
date added to LUP
2019-06-19 14:48:06
date last changed
2019-06-25 14:45:18
@misc{8982905,
  abstract     = {The use of boards as facades and sheathing is today common practice. Facade and sheathing boards are located far out in the building envelope and are thus subjected to variations of the surrounding relative humidity and temperature. Recently different kinds of damage on the boards have been brought to attention. The damage is varying and include cracking or warping of the boards. The damage may depend on moisture and thermal induced movement in the boards and it is therefore of interest to study these movements.
 
The main purpose of this master's thesis is to evaluate the magnitude of moisture and thermal induced movement for different boards. The boards include four fibre cement boards, one cement particle board, one gypsum board and one calcium silicate board.
 
Essential theory of moisture and heat is presented using relevant literature. The moisture and thermal induced movements were obtained by placing samples of the boards in different generated climates. Different relative humidities were generated using climate boxes and different temperatures were generated using ovens. Moisture and thermal induced movements and also sorption isotherms were evaluated for all boards.
 
The result includes sorption isotherms of all boards. The result also includes the moisture induced movements between 0 %, 33 %, 95 % and 100 % relative humidity, during both absorption and desorption. The thermal induced movements between 20 °C and 105 °C are also included in the result. 
 
The results show that the moisture induced movements of the boards generally are the largest for the cement particle board. The gypsum board has one of the smallest moisture induced movements. Most boards exhibit considerably larger shrinkage than swelling. The moisture induced movements are generally large between 0 % to 33 % relative humidity and between 95 % to 100 % relative humidity. The thermal induced movements are the largest for the gypsum board, followed by the fibre cement boards and the cement particle board. The calcium silicate board exhibits the smallest thermal induced movements. 
 
Which of the moisture or thermal induced movements that is the largest differ a lot between the boards and depend on which interval of temperature and relative humidity the board is exposed to. The moisture induced movements are considerably larger than the thermal induced movements for the cement particle board. The gypsum board shows considerably larger thermal than moisture induced movements.},
  author       = {Jönsson, Anton and Remnetorp, Daniel},
  keyword      = {Fibercementskiva,cementbunden fiberskiva,oorganisk kompositgipsskiva,gipsskiva,kalciumsilikatskiva,cementspånskiva,längdutvidgningskoefficient,krympning,svällning,töjning,sorption,sorptionsisoterm,relativ fuktighet,klimatbox Fibre cement board,cement particle board,inorganic composite gypsum board,calcium silicate board,coefficient of thermal expansion,swelling,shrinkage,strain,isotherm,moisture content,relative humidity,climate box},
  language     = {swe},
  note         = {Student Paper},
  series       = {LUTVDG/TVBM},
  title        = {Fukt- och temperaturrörelser i fasad- och vindskyddsskivor},
  year         = {2019},
}