Some properties of thermal insulating cement mortar using Ponza aggregate

Abstract Lightweight aggregate (LWA) mortar is made using lightweight or low-density aggregate, which improves properties such as thermal insulation, durability for freezing and thawing, fire and temperature resistance, and sound insulation. This research aims to use lightweight fine aggregate obtained from crushing natural rocks that are locally called “Ponza” to produce LWA mortar with different mix proportions to study the possibility of using it to produce blocks that can be erected on the outer side of the walls of old buildings to provide good thermal insulation. It also presents a study about the internal curing property of the produced cement mortar, which comes from the absorbed water by the used surface-saturated dry Ponza aggregate. The process includes using three mix proportions (1:1, 1:0.7, and 1:0.5) by weight of cement: fine aggregate. The samples were cured by dividing them into five groups, including moist curing for 1, 3, 7, and 28 days and the fifth group was moist cured for 1 day and then covered by a thin layer of flan coat. Dry density, compressive strength, flexural strength, and thermal conductivity for ages (7, 28, and 56 days) have been tested. The findings indicate that it is possible to produce thermal insulating lightweight cement mortar with mixtures of 1:0.7 or 1:0.5 cement to LWA, using Ponza aggregate, since the results showed an acceptable range of compressive and flexural strengths reaching about 14.75 and 2.91 MPa, respectively, a bulk density of less than 1,600 kg/mm 3 , and a lower thermal conductivity than many building materials.