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- Roots, Peter, et al.
(author)
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Frost Heave in Swedish Slab-on-Grade
- 2004
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In: Thermal Performance of the Exterior Envelopes of Whole Buildings. - 2166-8469.
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Conference paper (peer-reviewed)abstract
- This paper discusses the risk for frost heave in modern Swedish slab-on-grade. Theoretical simulations are undertaken in order to model the frost front below the slab. Different designs of the slab-on-grade for a north (Luleå) and a south (Lund) location in Sweden are studied. For example, the insulation thickness below the slab is varied and frost protection insulation is applied with different thicknesses and widths. The results show that there is a risk of frost heave. In a well-insulated slab-on-grade, the frost front will extend below the edge beam of the slab. However, with frost protection insulation, the depth of the frost front below the slab will be reduced significantly. Frost heave must be considered in the design process for a modern Swedish slab-on-grade.
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- Roots, Peter, 1962-
(author)
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Fukttransport i auto-klaverad lättbetong : En teoretisk simulering
- 1998
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Reports (other academic/artistic)abstract
- Genom byggproduktdirektiven (CPD) ställs krav på byggnadsmaterialstillverkarna som innebär att byggnadsmaterial skall livslängdsdeklareras. Därför har en grupp av byggnadsmaterialstillverkare starta ett projekt i samarbete med KTH och Högskolan Gävle-Sandviken där man studerar nedbrytning av lättbetong.Avsikten med denna rapport har varit att genomföra teoretiska simuleringar med avseende på fukttransport i en yttervägg av autoklaverad lättbetong. Simuleringarna har genomförts med ett PC-program kallat 1D-ham. Med PC-programmet har fuktflöden i en yttervägg under icke stationära förhållande (varierande utomhusklimat) simulerats med uppmätta klimatdata.Resultaten från simuleringarna har visat att relativa fuktigheten är över 90 % stora delar av året i olika väderstreck i en yttervägg. I en södervägg har relativa fuktigheten i det närmaste varit konstant över 90 % cirka 25 mm in i väggen från ytterytan. I de övriga väggarna sjunker relativa fuktigheten under sommaren för att bli i det närmaste konstant i hela väggen under sensommaren.Fukthalten i ytterväggen har för de skikt där relativa fuktigheten överstigit cirka 80 % varierat starkt. För skikten där relativa fuktigheten varit under cirka 80 % har fukthalten i det närmaste varit konstant.På basis av simuleringsresultaten har följande slutsatser har dragits.• Relativa fuktigheten kan vara i det närmaste 100 % under en del av ett år för en yttervägg i ett väderstreck.• Fukthalten varierar starkt under ett år i den del av ytterväggen som är nära ytterytan.• Relativa fuktigheten på sommaren är i det närmaste är konstant i hela ytterväggen.• Temperaturvariationerna ökar i skikt nära väggens ytterytan, vilket beror på väggens värmekapacitet.
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| 8. |
- Roots, Peter, et al.
(author)
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Heat loss due to thermal bridges in a foundation with floor heating
- 2007
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In: Thermal Performance of the Exterior Envelopes of Whole Buildings. - 2166-8469.
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Conference paper (peer-reviewed)abstract
- This paper provides an overview of the heat losses through the thermal bridge in the junction between a wall and a slab on grade at the perimeter of the foundation. First, the paper discusses the heat losses through the thermal bridge. In particular, the additional heat loss through the thermal bridge due to floor heating. In addition, the paper provides a thorough description of the total heat loss through the thermal bridge in the junction slab on grade and the wall. The result may be used in order to calculate the heat loss through the building envelope of a building.
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- Roots, Peter
(author)
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Heat transfer through a well insulated external wooden frame wall : an investigation of the effects of normal defects in the insulation resulting from incident wind and air flow through the wall
- 1997
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Doctoral thesis (other academic/artistic)abstract
- The heat requirement of a building can turn out to be greater than was calculated at the design stage. The reason for this may be that heat transport though the building envelope is greater than expected. This in turn can be due to the structure not fulfilling the design requirements in respect of windtightness and airtightness. In addition, there may be defects in the quality of the workmanship of the insulation that significantly reduce the thermal resistance of the external wall. The objective of this investigation has been to ascertain how normal variations in the insulation can affect heat transport through a well insulated wooden frame external wall under the influences of incident wind or wind flow through the wall. These 'normal variations' have been taken to be the presence of electrical conduits, breaks in the insulation, airgaps and nogging pieces, either singly or in combination. For incident wind, measurements in a hotbox and theoretical simulations have shown that the presence of electrical conduits, breaks in the insulation, airgaps or nogging pieces in a well insulated wooden frame external wall, whether singly or in combination, have negligible effect on thermal transport when subjected to incident wind. Heat transport is affected, however, by the presence of a break in the insulation: the combination of electrical conduits, airgaps, a nogging piece and a 16 mm gap in the insulation increased the U value of the wall by 0.028 W/(m²·K) at the most. Measuring the effects of a flow of air through the insulation involved simulating a break in the air seal. A pressure difference of between 10 Pa and 20 Pa was established, causing air to flow from the cold side to the warm side. Measurements and calculations have shown that normal variations in the insulation have a negligible effect on the transmission losses on the cold side, due to the heat exchange effect of the insulation, which raises the temperature of the air flowing through it. This has meant that as the air flow increases, the transmission losses on the cold side have decreased while those on the warm side have increased. Air flow through a wall does not necessarily mean that the heat demand of the building will increase.
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