Mechanical and thermal performance of engineered cementitious composite concrete produced by using polyvinyl alcohol fibers

Abstract

The inclusion of polyvinyl alcohol fiber (PVA) into an engineered cementitious composite (ECC) material is essential to impart mechanical and thermal properties, in addition to the enhancement of porosity and microstructural properties. Therefore, this improvement can be achieved by utilizing four different percentages of fiber (0.5, 1, 1.5, 2)%, replaced by volume. Five mixes of (PVA-ECC) of M25 grade strength were produced and tested at three different ages (7, 28, and 90) days. Because of the more porous structure of (PVA-ECC), the results demonstrated that adding 2% by weight of (PVA) fiber to (PVA-ECC) dramatically lowered its thermal conductivity by 36.5% compared to traditional concrete. However, more thermal energy can be captured and concentrated at the cement paste surface with the increasing amount of (PVA) fiber, causing an increment in thermal load and negatively affecting thermal insulating efficiency. Furthermore, compressive strength results revealed an upward trend as the fiber content increased up to 1.5% of (PVA) fiber, demonstrating the maximum improvement in strength. On the other hand, the achievement of 55% of the modulus of rupture by inclusion (2%) (PVA) fiber reveals that the modulus of rupture is mainly influenced by (PVA) fiber inclusion. Finally, there is confidence that the reduced thermal conductivity, hydrophobic surface nature, and improved mechanical characteristics of (PVA-ECC) can meet the demanding standards of environmentally friendly building construction.

Keywords

• engineered cementitious composite
• compressive strength
• microstructural investigation
• modulus of rupture
• thermal conductivity