INFLUENCE OF HYDROXYPROPYLMETHYLCELLULOSE ON THE MECHANICAL AND THERMAL PROPERTIES OF MORTARS WITH REPLACEMENT OF NATURAL SAND BY EXPANDED VERMICULITE
Thermal insulation, low density, HPMC, vermiculite.
Insulating and low-density cementitious materials have been increasingly studied in order to improve thermal insulation conditions in buildings and the possibility of reducing the weight of buildings. One of the ways to develop this type of material is through the use of light aggregates or additives that allow the incorporation of air. Thus, this study aims to verify the influence of the use of Hydroxypropylmethylcellulose (HMPC) on the thermal and mechanical properties of light mortars based on expanded vermiculite. Therefore, the tests of compressive strength and tensile strength in bending, water absorption by immersion, mass density, modulus of elasticity and water loss by evaporation were performed. The thermal performance was obtained through the simplified method of NBR 15575 (ABNT, 2013) and through a simulator. The results indicate that the incorporation of HPMC causes an increase in the void index, which causes a reduction in mechanical strength and modulus of elasticity. It is also noted that the incorporation of HPMC produces a mortar with a lower mass density, reflecting in a lighter material, increasing its thermal insulation capacity, in such a way that the 100% vermiculite composition can insulate approximately 20ºC, while the complete system (mortar+brick+mortar) insulates approximately and 43ºC, values that are higher when compared to the mortar without incorporation of HPMC. Thus, it is concluded that HPMC caused an increase in thermal insulation in light mortars based on vermiculite, through the increase in the void index, directly influencing the mechanical properties of the material.