STRENGTH ASSESSMENT OF YOYO SAND CONCRETE PAVING STONES

Abstract

This paper reports the results of an investigation of strength assessment of interlocking paving stones using Yoyo sand either wholly or as a partial replacement of river sand in concrete. 270 Nos of "double T" shaped concrete paving stones, (Thickness 60mm; Area=29587m²) with varying mix ratio of Yoyo/ Natural river sand were tested. The mix ratios used were 1:2:4 and 1:3:6 with corresponding ratio of 0.65 and 0.75 respectively. The percentage content of Yoyo sand in the fine aggregate was varied from 0 to 100% in steps of 25%.

The results of the investigation showed that the presence of Yoyo sand in the concrete increased the strength characteristics compared to natural river sand. However, 50% replacement of river sand by Yoyo sand should be avoided as there was abnormal behaviour in this grade. Also, early development of compressive strength by Yoyo sand makes it a better choice over river sand in the production of paving stones. The compressive strength result shows that 1:2:4 mix ratio with 0.65 can be used for light traffic pavers while 1:3:6 mix ratio with = 0.75 can only be suitable for walkway pavers. Yoyo sand can therefore be considered as a better total or partial substitute for river sand in paving stones production.