Study on applicability of ACI and DoE mix design methods for paving blocks

Abstract

Applicability of either ACI or DoE mix design method for paving blocks is limited in the published literature. Further, small scale paving block manufacturers struggle at the initial stages to come up with mix proportions. In view of the above, a comparative study on both ACI and DoE mix design methods, to select the initial mix proportion for the paving blocks was carried out in the present study.

Quantities of constituents were estimated for characteristic compressive strengths (cylinder strength for ACI method and cube strength for DoE method), from 15 N/mm2 to 50 N/mm2. Based on the estimated proportions, trial mixes were cast and tested for compression at 7 and 28 days. When paving blocks are mix proportioned as per ACI mix design method, the achieved compressive strengths are higher than the compressive strength requirements of Sri Lankan Standard for paving blocks. Whereas a correlation being observed between the achieved compressive strength of paving blocks and the grade designation. Similarly, when paving blocks are mix designed as per the DoE mix design method, the achieved compressive strengths satisfied the compressive strength requirements of Sri Lankan Standard for Classes 2, 3 and 4 roads.