Characterization of compaction and CBR properties of recycled concrete aggregates for unbound road base and subbase materials in Vietnam
30/12/21 05:43PM
Hong Nam Thai, Tien Dung Nguyen, Van Tuan Nguyen, et al. Journal of Material Cycles and Waste Management, 2021.
Abstract:
Mechanical properties of recycled concrete aggregates (RCA) such as
compaction and California bearing ratio (CBR) are important for
application as unbound road base and subbase materials. Limited studies,
however, have examined the effects of the nominal maximum particle
diameter (Dmax) of aggregates and fines content (Fc; < 0.075 mm).
Also, particle rearrangement and breakage depend on water content (w)
(i.e., water states of aggregates) under the compaction process. In this
study, therefore, a series of compaction and CBR tests at different
compaction energies (Ec) and w was carried in the laboratory using
graded RCA with Dmax of 25 mm and 37.5 mm and four different Fc ranging
from 0 to 20%. The results showed that the compaction properties of RCA
were controlled by Ec and w. Based on the analysis of water states of
aggregates, it can be understood that water existed in the capillary
region for maximum dry density and existed at the boundary between
capillary and hygroscopic regions for minimum dry density. The maximum
measured CBR values were attained at Fc = 5% for both Dmax of 25 mm and
37.5 mm. The breakage of samples became enhanced with increasing Ec and
weakened with increasing Fc.
