| Popis: |
Reliability estimates of unconfined compressive strength values from laboratory results for specimens compacted at British Standard Light (BSL)for compacted quarry dust treated black cotton soil using cement for road sub – base material was developed by incorporating data obtained from Unconfined compressive strength (UCS) test gotten from the laboratory test to produce a predictive model. Data obtained were incorporated into a FORTRAN-based first-order reliability program to obtain reliability index values. Variable factors such as water content relative to optimum (WRO), hydraulic modulus (HM), quarry dust (QD), cement (C), Tri-Calcium silicate (C3S), Di-calcium silicate (C2S), Tri-Calcium Aluminate (C3A), and maximum dry density (MDD) produced acceptable safety index value of1.0and they were achieved at coefficient of variation (COV) ranges of 10-100%. Observed trends indicate that WRO, C3S, C2S and MDD are greatly influenced by the COV and therefore must be strictly controlled in QD/C treated black cotton soil for use as sub-base material in road pavements. Stochastically, British Standard light (BSL) can be used to model the 7 days unconfined compressive strength of compacted quarry dust/cement treated black cotton soil as a sub-base material for road pavement at all coefficient of variation (COV) range 10 – 100% because the safety index obtained are higher than the acceptable 1.0 value. |
