Cement stabilized subgrades have been extensively used to improve the engineering
performance of pavement structures. Due to the effects of cementitious hydration,
pozzolanic reaction, as well as, cation exchange, chemical bonding is generated
between fine soil particles. Therefore, the geotechnical characteristics of difficult clay
soils will be improved in terms of plasticity, strength, stiffness, and durability. The
cement modified soils (CMS) will then function as a new pavement layer which
partially or totally preplaces the thickness of granular base layer as commonly found
in traditional road constructions. This paper first introduced a subgrade stabilization
project located in Chatham‐Kent, Ontario, followed by the field testing of subgrade
stiffness using a light weight deflectometer (LWD) test on the stabilized subgrade
surface. Five different low‐volume roads were chosen as test sections for LWD
stiffness test. The stiffness of the subgrades was measured before the construction, 3
hours after the stabilization followed by testing at 3 days, 7 days, 28 days, and 1 year
respectively. Field test results indicated a significant increase of the subgrade
stiffness after the cement stabilization and compaction; moreover, the stiffness
continued growing along with the curing time. Soil sampled from one of the test
sections was tested in lab facilities. Laboratory testing including: unconfined
compressive strength (UCS) at 7 days and 28 days, durability test and pH values test
for cement stabilized soil. Stabilized soil had 7 days UCS value of 0.83 MPa with 6%
cement, and 1.43 MPa with 12% cement. Moreover, 5% to 6% cement stabilized T38
soil specimens had improved durability properties against freezing and thawing and
met the weight loss limit requirements. Results also indicated that the cement
stabilization changed the soil environment from slightly acidic to alkaline, and
reduced the potential for growing of organics. It is also recommended future studies
evaluate mixes with supplementary cementing materials to provide a more
environmentally friendly stabilized subgrade. The paper finally introduces alternative
Hydraulic road binders (HRB) as a more economic, sustainable and environmentally
friendly solution to the construction and rehabilitation of Canada’s low‐volume
roads.
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