| This study optimizes soil-cement mixtures using locally sourced loess from Southeastern
Idaho, Portland Type II cement, and polycarboxylate superplasticizers to achieve structural-grade
performance while minimizing environmental impacts. Through systematic experimentation
varying cement contents (10–45% by weight) and superplasticizer dosages (up to 3%),
thixotropic mixes were developed, consisting of a fluid, homogeneous product without rodding
and rapid 1-day formwork removal. Under airtight curing, the optimal 30% cement with 3%
superplasticizer formulation attained an average 28-day unconfined compressive strength of
4,876 psi and average tensile strengths of 478 psi.
Vibration enhanced strengths by an average of 18% with the most optimal mix increasing
strength from 4,876 psi to 5,831 psi via improved particle packing. Freeze-thaw tests showed
moderate degradation but sufficient resilience for road bases and embankments. Water bath
curing reduced the average strengths from 4,876 psi to 2,808 psi, underscoring moisture
sensitivity in variable climates such as in Southeastern Idaho. Preliminary tests with kaolinite
and bio-graphene additives alone and with cement revealed potential for cohesion and packing
but inconsistent hydration interference, necessitating refined dosages. From an economic
perspective, native loess may reduce sourcing costs by up to 50%.
The results demonstrate the viability of soil-cement for sustainable infrastructure, bridging
the affordability of adobe with concrete durability for application in low-income housing and
pavements in collapsible soil regions. Challenges include tensile brittleness and field moisture
protection which may be addressed by use of fibers and air-entrainers. Research into freeze thaw
durability showed results adequate to meet subbase requirements for the southeastern Idaho
roads. Future work should consider field trials and carbon-neutral supplementary cementitious
materials (SCMs) to scale adoption, advancing resilient, eco-friendly construction amid
escalating global housing demands.
Keywords: soil-cement optimization, superplasticizer additives, sustainable infrastructure |