The influence of nanoclay and styrene-butadiene rubber (SBR) latex on the mechanical properties, durability, thermal resistance and microstructure of fly ash-slag geopolymer mortar is focused on in this research. The effect of nanoclay addition in different percentages of 2%, 4%, 6%, 8% and 10%, and the effect of SBR latex in different percentages of 5%, 10% and 15% are investigated. More in detail, the considered mechanical properties include compressive strength, split tensile strength and flexural strength; while the durability properties were water absorption, sorptivity, drying shrinkage, chloride permeability, acid resistance and sulphate resistance. The thermal resistance was assessed through weight loss and residual compressive strength after being exposed to temperatures of 200 °C, 400 °C, 600 °C and 800 °C. Furthermore, discrete polyvinyl alcohol (PVA) fibres in different percentages of 0.5%, 1.0% and 1.5% volume of mortar were added into the optimum mix aimed at the crack arresting properties and to modify the failure from brittle to ductile. The addition of nanoclay at an optimum dosage of 6% of binder resulted in better mechanical, thermal and durability properties. The addition of nanoclay and SBR latex resulted in lower water absorption and sorptivity, and the drying shrinkage and moisture movement also reached the specified limits of 0.09% and 0.06%. Moreover, the chloride permeability was reduced from moderate to low, and the resistance in acidic and sulphate environments was also enhanced. Even though the addition of SBR latex exhibited better mechanical properties and durability, the thermal resistance was lower after a temperature of 200 °C, due to the lower melting point of SBR. The strength degradation in geopolymer mortar at high temperatures was mainly due to dehydration and dehydroxylation leading to thermal incompatibility between geopolymer matrix and aggregates. The addition of PVA fibre has an increase in tensile and flexural strength at 1% fibre by volume. The SEM images show a more even microstructure with reduced microcracks in geopolymer mortar with nanoclay. FTIR analysis shows an improved degree of geopolymerisation by the addition of 6% nanoclay, and the addition of SBR latex has only physical interaction contributing to better mechanical properties and durability.
Effect of addition of nanoclay and SBR latex on fly ash-slag geopolymer mortar
Cascardi A.;
2023-01-01
Abstract
The influence of nanoclay and styrene-butadiene rubber (SBR) latex on the mechanical properties, durability, thermal resistance and microstructure of fly ash-slag geopolymer mortar is focused on in this research. The effect of nanoclay addition in different percentages of 2%, 4%, 6%, 8% and 10%, and the effect of SBR latex in different percentages of 5%, 10% and 15% are investigated. More in detail, the considered mechanical properties include compressive strength, split tensile strength and flexural strength; while the durability properties were water absorption, sorptivity, drying shrinkage, chloride permeability, acid resistance and sulphate resistance. The thermal resistance was assessed through weight loss and residual compressive strength after being exposed to temperatures of 200 °C, 400 °C, 600 °C and 800 °C. Furthermore, discrete polyvinyl alcohol (PVA) fibres in different percentages of 0.5%, 1.0% and 1.5% volume of mortar were added into the optimum mix aimed at the crack arresting properties and to modify the failure from brittle to ductile. The addition of nanoclay at an optimum dosage of 6% of binder resulted in better mechanical, thermal and durability properties. The addition of nanoclay and SBR latex resulted in lower water absorption and sorptivity, and the drying shrinkage and moisture movement also reached the specified limits of 0.09% and 0.06%. Moreover, the chloride permeability was reduced from moderate to low, and the resistance in acidic and sulphate environments was also enhanced. Even though the addition of SBR latex exhibited better mechanical properties and durability, the thermal resistance was lower after a temperature of 200 °C, due to the lower melting point of SBR. The strength degradation in geopolymer mortar at high temperatures was mainly due to dehydration and dehydroxylation leading to thermal incompatibility between geopolymer matrix and aggregates. The addition of PVA fibre has an increase in tensile and flexural strength at 1% fibre by volume. The SEM images show a more even microstructure with reduced microcracks in geopolymer mortar with nanoclay. FTIR analysis shows an improved degree of geopolymerisation by the addition of 6% nanoclay, and the addition of SBR latex has only physical interaction contributing to better mechanical properties and durability.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
