Mechanical Properties of Eco-Friendly and Energy-Saving Mortar with Porous Feldspar

Abstract

ABSTRACTPorous feldspar is a silicate mineral that is made up of more than 80% of SiO2 and Al2O3 as components. It has a large specific surface area than sand. It has an excellent reactivity with cement as a pozzolanic component. A normal mortar as a construction material is composed of 75% of sand and 25% of cement. Carbon dioxide (CO2) is a cause of environmental pollution. It is often made when making cement contained in mortar. Therefore, it is necessary to study alternative materials that can reduce the amount of cement used. This study was conducted using feldspar as a fine aggregate instead of sand. First, feldspar was standardized through physical testing. Compressive strength tests were then carried out to compare feldspar mortar and sand-based mortar. Hydration products of mortars were confirmed using a scanning electron microscope (SEM). Result of these tests revealed that when feldspar was used, the compressive strength tended to be high. In this study, Case 3 consisting of feldspar 80% and cement 20% with reduced use of cement was found to be the most suitable one. Secondly, to confirm the appropriateness of using feldspar mortars as a floor material, thermal conductivity and thermal efficiency experiments were conducted using mortars with ingredients that differed from a normal mortar. Results of these experiments revealed that feldspar mortar was more effective as an insulating material than a normal mortar because it had lower thermal conductivity and longer heat retention time than a normal mortar. Therefore, the use of feldspar mortar could have an energy reduction effect compared to a normal mortar as a flooring material in an ondol (under-heating) type floor-heating system in Korea.