Effect of four-component binder on characteristics of self-compacting and fibre-reinforced self-compacting mortars

Abstract

The hydration heat of a four-component binder consisting of Portland cement (CEM I 42.5 R), blast-furnace slag (BFS), metakaolin (MK), and silica fume (SF) was investigated using a conduction calorimeter and thermal analytical method to optimize the material composition of self-compacting mortar (SCM). Then, the influence of material composition with different substitution levels (0, 25, 30, and 35% labelled as SCM100, SCM75, SCM70, and SCM65) on physical and mechanical properties of the mortars with two volumetric binder sand ratios of 1:1 and 1:2 (cement: sand) was evaluated. Furthermore, two mortar compositions comprising SCM75 and sand at 1:1 and 1:2 ratios were used to prepare fibre-reinforced self-compacting mortars in five combinations (0, 0.25, 0.5, 0.75, and 1%) of two fibres (polypropylene-PPF and basalt-BF) at a constant content of 1.00 vol%. The properties of the prepared samples were investigated with respect to the characteristics of self-compactibility and mechanical properties of fresh and hardened states, respectively. The rheology characteristics expressed by slump flow, V-funnel, and T20 were found following the EFNARC guidance. The partial replacement of cement by supplementary cementitious materials has enhanced the performances (compressive and flexural strengths, dynamic modulus of elasticity) of self-compacting mortars from the 7th day through pozzolanic activity. Furthermore, adding fibres has enhanced the DME and microstructure of the self-compacting mortars.The hydration heat of a four-component binder consisting of Portland cement (CEM I 42.5 R), blast-furnace slag (BFS), metakaolin (MK), and silica fume (SF) was investigated using a conduction calorimeter and thermal analytical method to optimize the material composition of self-compacting mortar (SCM). Then, the influence of material composition with different substitution levels (0, 25, 30, and 35% labelled as SCM100, SCM75, SCM70, and SCM65) on physical and mechanical properties of the mortars with two volumetric binder sand ratios of 1:1 and 1:2 (cement: sand) was evaluated. Furthermore, two mortar compositions comprising SCM75 and sand at 1:1 and 1:2 ratios were used to prepare fibre-reinforced self-compacting mortars in five combinations (0, 0.25, 0.5, 0.75, and 1%) of two fibres (polypropylene-PPF and basalt-BF) at a constant content of 1.00 vol%. The properties of the prepared samples were investigated with respect to the characteristics of self-compactibility and mechanical properties of fresh and hardened states, respectively. The rheology characteristics expressed by slump flow, V-funnel, and T20 were found following the EFNARC guidance. The partial replacement of cement by supplementary cementitious materials has enhanced the performances (compressive and flexural strengths, dynamic modulus of elasticity) of self-compacting mortars from the 7th day through pozzolanic activity. Furthermore, adding fibres has enhanced the DME and microstructure of the self-compacting mortars.