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Innovative Design of Thermal Insulating Green Rendering Mortar for Energy Efficient Buildings
Oral Presentation
Authors
Housing and Building National Research Center
Abstract
Improving the thermo-physical properties of plastering or rendering mortar is an effective trend to reduce the building’s energy consumption. The objective of this study is to develop an eco-friendly lightweight (LW) thermally resistive one-coat rendering mortar. A green or low-carbon limestone-calcined clay cement (LC3) binder was prepared by substituting 60 wt% of the white Portland cement (WPC) with a blend of limestone (LS) powder and metakaolin (MK) with a LS:MK ratio of 1:2 (wt%). The binder has been mixed with exfoliated vermiculite (EVM) aggregate with various aggregate volume contents of 25, 50, and 75%. Compressive and indirect tensile strengths, volume of permeable voids (VPV), water absorption, bulk density, thermal conductivity (TC), and microstructure of the hardened mortars have been investigated after 28 days of hydration. The results revealed that the newly developed mortars fulfil the standard technical requirements for thermally insulating renders. The mortar incorporating 75 vol. % EVM possesses the lowest TC (0.19 W/m.K.) and the lowest compressive strength (10.23 MPa); furthermore, it reduces thermal loads or heat flow into buildings by 30%. The scanning electron microscopy (SEM) showed adequate bonding and a dense interfacial transition zone between the EVM and the LC3-binder matrix.
Keywords
Green binder; rendering; exfoliated vermiculite; thermal conductivity; Compressive strength; Fire resistance; thermal loads
Subjects