Abstract
Graphene Nanosheets (GNs) have been successfully added to the palm oil fuel ash (POFA) based geopolymer with KOH activator to improve the geopolymer compressive strength. The graphene was synthesized using turbulence assisted shear exfoliation (TASE) method and identified using Raman spectroscopy. The influence of concentrations and weight percent of graphene against the compressive strength, porosity, and morphological properties were investigated. The crystallinity phases of geopolymer and graphene were also identified using XRD. Raman spectroscopy revealed that graphene produced by TASE method had ≥ 3 layers (graphene nanosheets, GNs). Furthermore, Raman maping constructed by the intensity D band showed the graphene had different atomic arrangements at the edge (armchair and zigzag). The compressive strength and the porosity tests showed that increasing the concentration and the weight percent of graphene increased the compressive strength and reduced the porosity. The highest compressive strength and the lowest porosity (10.8 MPa and 5.92%, respectively) were exhibited by the geopolymer synthesized using 0.7 wt% graphene with concentrations of 30 mg/ml. The SEM micrographs indicated that the graphene reduced the porosity of geopolymers with a pores fulfilling mechanism due to of very small of graphene nanosheets size (∼60 - ∼80 nm).
Highlights
IntroductionThe problem that has arisen so far is that the mortar or concrete made from conventional cement has some major weakness, namely, high energy consumption in production and CO2 gas disposal which is highly detrimental to the environment
Mortar and concrete are the essential elements in the field of construction
Raman spectroscopy revealed that graphene produced by turbulence assisted shear exfoliation (TASE) method had ≥ 3 layers
Summary
The problem that has arisen so far is that the mortar or concrete made from conventional cement has some major weakness, namely, high energy consumption in production and CO2 gas disposal which is highly detrimental to the environment. Geopolymer is the promising material to substitute the conventional cement (OPC). Geopolymer shows the same mechanical properties as OPC but with better performance in extreme environmental conditions. It has been reported that geopolymer showed excellent resistance to acid and sulfate attacks when compared to OPC [2].
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