Effectiveness of geogrid in cement treated crushed rock for the base of pavement

This research studies improving the quality of cement treated
crushed rock as base layers of pavements by reinforcing
geogrid materials. The grain sizes of crushed rock used are
according to the standards of the Department of
Highways.Compressive strength tests were conducted on test
samples under with curing times of 7 days and 28 days. Three
cement values (0.5%, 1%, and 2%) and three types of
reinforcement geogrid (one type of uni-axial and two types of biaxial)
was considered. The position of the reinforcement mesh is
in ratios of 1/3, 1/2, and 2/3 relative to the sample height.
Unconfined compression tests are conducted to determine the
modulus (E50) and maximum compressive strength (qpeak), while
3-point bending tests are used to study cracking behavior and
determine the equivalent flexural strength ratio (RDT,1 5 0 ). The
results indicate that increasing cement content leads to higher
compressive strength. Adding reinforcing geogrid also enhances
compressive strength, though the different types of geogrids did
not significantly affect this increase. The uniaxial geogrid shows a
improvement on flexural strength. In additions, analysis results of
the equivalent bending ratio show that adding reinforcement
geogrid alters bending behavior from softening to hardening, and
reduce the occurrence of reflection cracks.