# A Comparative Evaluation of Cement and By-Product Petrit T in Soil Stabilization
## 4 Conclusions  
The present study presents a comparative evaluation of the effect of two different binders on the physical and engineering properties of soil after treatment. The study cover both short- and long-term effects and the following conclusions can be drawn:  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Binder** \\ **Content** \\ **\%** \\ \end{tabular} } & \multicolumn{2}{c}{\begin{tabular}{c} **Enhancing in Soil** \\ **Strength, q\({}_{u}\)** \\ **\end{tabular} } & \multicolumn{2}{c}{\
\begin{tabular}{c} **Enhancing in Soil** \\ **Stiffness, E\({}_{50}\)** \\ **\end{tabular} } & \multirow{2}{*}{**Failure Strain \%**} & \multicolumn{3}{c}{
\begin{tabular}{c} **E\({}_{50}\) = q\({}_{u}\)** \\ **(Upper and Lower Range)** \\ \end{tabular} } \\ \cline{2-9}  & **Cement** & **Petrit T** \\ \hline
**0** & 1 & 1 & 1 & 1 & 24 & 24 & 6 & 10 & 6 & 10 \\ \hline
**1** & 2 & - & 4 & - & 15 & - & 15 & 18 & - & - \\ \hline
**2** & 4 & 2 & 9 & 4 & 9 & 14  
* Cement is more effective on improving the physical and engineering properties of treated soil. The same effect can be achieved by using the double amount of Petrit T and long curing periods.
* Adding small percentages of the two binder types (up to 10%) has approximately the same trend of behaviors in terms of the decrease the plasticity index. Cement has more effect with further increases in binder content.
* The addition of dry binders of cement and Petrit T have an immediate effect on decreasing the initial water content. In addition, further reduction in soil water content can be observed over time. The reduction in soil water content has a more dominant effect from cement during the first 28 days of curing, compared to Petrit T, which shows gradual decreases in water content over time.
* The density of treated soil with cement and Petrit T is increased with increasing binder content and curing time.
* Liquidity index and the water content to plastic limit ratio are introduced as new indices to define the improvement in the workability of treated soil directly after treatment and over time. The workability improved immediately after treatment with the reduction in the liquidity index. Continuous improvement in soil workability is observed over time due to a further reduction in the liquidity index within the plastic range when the liquidity index (LI) \(>\) 0 or when the water/plastic limit ratio is more than one.
* Axial failure strain was decreased as the binder content and curing time increased with greater effect upon cement treatment. Treated soil with 7% cement exhibits a more brittle failure compared to the lower cement content and Petrit T, which shows a more ductile behavior. The failure mode is gradually changed from ductile to brittle failure compared to soil without treatment.
* The pH value of treated soil can provide a useful assessment of the soil-binder reaction. A pH value below 10 is not enough to initialize the pozzolanic reaction and subsequently provides further cementing components over time.
* The particle size distribution curves change towards the granular side by reducing the clay size fraction and increasing the silty size fraction after treatment with a more pronounced effect for cement treatment. This effect is increased with an increase in binder content.  
Conceptualization, W.A.-J. and J.L.; methodology, W.A.-J.; validation, W.A.-J., J.L., S.K. and N.A.-A.; formal analysis, W.A.-J.; investigation, W.A.-J.; Visualization, W.A.-J., J.L., S.K. and N.A.-A. Writing--original draft preparation, W.A.-J.; writing--review and editing, J.L.; supervision, J.L., S.K. and N.A.-A.  
This research received no external funding.  
The first author thanks the Iraqi Ministry of higher education for offering the scholarships.  
The authors declare no conflict of interest.