Effect of Compaction Delay on the Strength of Cement Modified Crushed Rock Base

Abstract

Shallow cement mixing is one of soil improvement techniques to blend cement into roadwork materials which is characteristically low water material. To do so, compaction procedure is required to homogenize soil particles, water and cement. The strength development of soil cement is due to hydration reaction of cement and water constituted within 2 to 3 hours afterward. In accordance with the standard of Department of Highways for the soil cement roadwork, the working time should not exceed 2 hours. However, the compaction is occasionally delayed due to some construction sites located in restricted area or partially allowed accessibility by transport services. This research is therefore to present the ability of soil cement for determining higher working time. The test differed compaction time after soil mixed with cement was 1, 2, 3 and 4 hours respectively. Results indicated that working time for compaction was contributed by the amount of cement.  Cement mixture at 2% by weight of dry soil enables the compaction to perform within 2-3 hours for crushed rock mixed with cement. While crushed rock and recycled road materials mixed with cement requires cement mixture at 4% by weight of dry soil to perform the compaction for 2-3 hours.