Measurement of water absorption of very fine particles using electrical resistivity

This paper presents an electrical resistivity method for measuring water absorption of very fine particles, making it easier to characterize stock materials that may be recycled in construction applications. The fine particles of interest in this study come from recycled concrete, limestone, and natural sand sources, and retained on No. 100 and No. 200 sieves. The electrical resistivity of fines is used to indicate water content. The saturated surface-dry (SSD) state is defined as a percolation threshold that is detected using electrical resistance measurements. This study shows that recycled concrete fines exhibit a higher percolation threshold than of limestone and natural sand fines. The percolation threshold value of the water content is not sensitive to mold shape (cylinder and prism) and resistivity measurement method (two-probe and fourprobe methods). The results suggest that this method is an easy and reproducible means for measuring the water absorption of recycled fines, thus addressing a serious barrier to their wide acceptance in practice.