An experimental investigation on the impact of lime and cement mortar/plaster material on the indoor hygrothermal environment of test spaces

Abstract

The study’s objective was to investigate and quantify the heat and moisture transfer through two walls of a 1m2 area facing south, located in Ahmedabad, Gujarat, India. One of the walls was constructed with lime mortar, and the other with cement mortar and XPS (Extruded Polystyrene) blocks of size 230 x 100 x 75 mm, coated with an inner plaster layer of the same materials. Other walls were made up of EPS (Expanded Polystyrene), thus limiting the heat and moisture transfer only through mortar layers. The mortar joints on the exposed wall accounted for 17% of the total surface area of the wall. The study monitored the temperatures, relative humidity, and surface temperatures inside the two identical test cells of 1 m3 volume each for 54 days from 1st March to 23rd April 2023. Also, a 3-day moisture test was carried out to check the effect of vapor permeability. The research questions are as follows. • Is the hygrothermal environment different for cement and lime mortar cells? • Will the cement mortar produce higher heat ingress due to high conductivity? • Will the higher thermal mass of cement make a difference in the hygrothermal environment of the cells?