Physical and mechanical properties of hemp fibre reinforced alkali-activated fly ash and fly ash/slag mortars

Two alkali-activated mortars with different solid prime materials were analysed. The first mortar contained fly ash, had lower density, higher water absorption, lower compactness, lower compressive strength, similar flexural strength and was less brittle than the second one with fly ash + slag. The addition of hemp fibres slightly changed the mortars' density, water absorption, compressive and flexural strength, however significantly increased its energy absorption capacity. The initially more brittle matrix exhibited significantly higher relative toughness increase. The smoother and less porous fibre/matrix interface assured through numerous fibre/matrix contact points a more optimal fibre/matrix interfacial bond- and frictional stress transfer. (C) 2020 Elsevier Ltd. All rights reserved.