Abstract
This experimental study investigates the effects of the aggregate surface conditions on the compressive strength of quick-converting track concrete (QTC). The compressive strength of QTC and interfacial fracture toughness (IFT) were investigated by changing the amount of fine abrasion dust particles (FADPs) on the aggregate surface from 0.00 to 0.15 wt% and the aggregate water saturation from 0 to 100%. The effects of aggregate water saturation on the compressive strength of the QTC and IFT were notably different, corresponding to the amount of FADPs. As the aggregate water saturation increased from 0 to 100%, in the case of 0.00 wt% FADPs, the IFT decreased from 0.91 to 0.58 MPa∙mm1/2, and thus, the compressive strength of the QTC decreased from 34.8 to 31.4 MPa because the aggregate water saturation increased the water/cement ratio at the interface and, consequently, the interfacial porosity. However, as the aggregate water saturation increased from 0 to 100%, in the case of 0.15 wt% FADPs, the compressive strength increased from 24.6 to 28.1 MPa, while the IFT increased from 0.41 to 0.88 MPa∙mm1/2 because the water/cement ratio at the interface was reduced as a result of the absorption by the FADPs on the surface of the aggregates and the cleaning effects of the aggregate surface.
Highlights
The traditional track system, a ballasted track, is still widely regarded as one of the favored options for new railway construction projects due to low construction costs and easy maintenance
The interfacial fracture toughness (IFT) was calculated using the calculated using the formula found in Lee et al [4], which is given in fracture mechanics by formula found in Lee et al [4], which is given in fracture mechanics by Anderson [23]
The compressive strength of quick-converting track concrete (QTC) and IFT between the aggregates and quick-hardening mortar (QM) was investigated by changing the amount of fine abrasion dust particles (FADPs) on the surface of the aggregate and the content of aggregate water saturation
Summary
The traditional track system, a ballasted track, is still widely regarded as one of the favored options for new railway construction projects due to low construction costs and easy maintenance This type of track requires frequent repairs as a result of periodic train loads [1,2,3]. Lee et al [4] assessed the effects of FADPs on interfacial fracture toughness (IFT) between quick-hardening mortar (QM) and ballast aggregates in order to develop a suitable QM with high IFT. They revealed that the use of coarser silica sands and silica fume could produce the required QTC strength with a minimum cleaning process of existing ballast aggregates
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