Effect of thermal insulation components on physical and mechanical properties of plant fibre composite thermal insulation mortar

Abstract

To improve the resource level of agricultural and forestry waste straws and fallen leaves, straw and fallen leaves fibres were used as organic thermal insulation components (TICs). Vitrified beads and closed-pore expanded perlite were used as inorganic TICs to prepare plant fibre cement-based composite thermal insulation mortar (TIM). The effects of TICs on physical and mechanical properties of TIM were studied by altering the types and contents of TICs. The results show that the fluidity of the TIM decreases with the incorporation of plant fibres in the vitrified bead + expanded perlite TIM. With the addition of wheat straw fibre and straw fibre, the homogeneity of TIM mixture is improved. Plant fibres have the characteristics of lightweight, porosity, water absorption and heat preservation, which increases water absorption and heat retention and a decrease in strength of the TIM. With the incorporation of three plant fibres of leaves, wheat straw and straw, the water absorption of TIM increased by 15.84, 5.47, and 4.54% respectively. At the same time, thermal conductivity decreased by 0.17, 0.19, and 0.20 W/(m.K), respectively, flexural strength decreased by 3.99, 2.63, and 2.44 MPa, and compressive strength decreased by 20.91, 17.13, and 19.25 MPa, respectively. After the expanded perlite and vitrified microbeads are modified with pure acrylic emulsion, the polymer film retains more pores inside the fibres, enhances the interface bonding with the cement-based material, which is helpful to improve the thermal insulation properties and strength of the TIM.

Keywords

• Modification
• Plant fibre
• Thermal insulation component
• Cement base
• Composite mortar
• Performance