Influence of natural and synthetic fibers on the permeability of cement mortars - sand, and, cement, lime and sand

Abstract

A common problem in masonry walls is moisture. Glue and plaster mortars can act as an impermeable barrier, reducing costs in future repairs. To determine the influence of synthetic polypropylene and natural fibers of cabuya (Furcraea Andina) (treated with paraffin) on the permeability of mortars. The depth test of water penetration under pressure (UNE-EN 12390-8) and the capillary water absorption rate test (ASTM C 1585-04) were performed. For which mortars (cement and sand) and mortars (cement, lime and sand) were manufactured with additions of polypropylene and cabuya fibers of 12 mm, in percentages of: 0.15%, 0.3% and 0.5% of the mortar volume. It was determined that polypropylene and cabuya fibers increase the depth of water penetration under pressure, even more so if the mortar contains lime. On the other hand, the addition of 0.15% polypropylene fibers, 0.15% and 0.3% cabuya fibers, decrease capillary absorption in the mortars (cement and sand). Similarly, the addition of 0.3% cabuya fibers decreases the capillary absorption rate of mortars at an initial stage. Lime mortars tend to absorb water at a higher rate in the initial stage, and in the secondary stage their absorption rate decreases compared to cement and sand mortars. Additionally, the simple compressive strength test was performed at 28 days. All mortars exceeded the resistance of 5.2 MPa established by the NTE INEN 2518 standard, for N-type mortars. The mortars with 0.3% cabuya fibers, reached the best resistance, the mortars (cement and sand) with 7.905 MPa and the mortars (cement, lime and sand) with 7.517 MPa.