Influence of the Aggregate Surface Conditions on the Strength of Quick-Converting Track Concrete

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 center dot mm(1/2), 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 center dot mm(1/2)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.