Strength, Toughness: Mineral Wool‐Polyethylene Pulp‐Reinforced Mortars

Abstract

Mortar sheet products can be made stiff and brittle by reinforcing with stiff fibers having strong chemical bonding to cement paste, such as asbestos. They can be made tough and pliable by reinforcing with softer fibers having poor bonding to cement, such as polypropylene, where the fiber stress is transferred over longer distances from developing cracks. It is also known that the stiffness and fracture energy of mortar can be altered by surface treatments of the fiber to either increase its bonding with the paste, making the composite stiffer, or to decrease its bonding, making the composite more pliable. Less understood are the increases in both stiffness and toughness of mortar by reinforcing it with fiber hybrids—one stiff and/or well‐bonded fiber combined with one soft and/or poorly bonded fiber. This study experimentally evaluates the synergism of combining mineral wool to improve stiffness and polyethylene pulp to improve toughness for mortar sheet products. A design example illustrates the determination of fiber weight ratios for specified bending stiffness and bending toughness at minimum material cost.