# Preparation of a Low-Cement-Content Silty Soil Stabilizer Using Industrial Solid Wastes
## 4 Conclusions  
Two mixtures with a low cement content were proposed and used as silt soil stabilizers, i.e., stabilizer A (cement:ground GBFS:fly ash:FGD gypsum = 30:44:15:11) and stabilizer B (cement:ground GBFS:fly ash:FGD gypsum = 40:38:13:9). The compressive strength development, CBR and temperature shrinkage, mineral compositions, and micromorphology of the stabilized soil were measured. The following conclusions can be drawn:  
* The compressive strength increased with the stabilizer dosage, and they showed a strong linear relationship. Longer delay times led to a lower strength. Notably, stabilizers containing large amounts of solid waste mitigated the adverse effect of the delay time on compressive strength. When the stabilizer dosage was 6%, both stabilizers A and B satisfied the standard even after 8 h of delay, which offered sufficient time for the operation at the construction site.
* Both stabilizers with a 4% dosage significantly improved the CBR. The specimens were soaked in water for 96 h, and their CBR value reached 60%, which was about seven times higher than the one (i.e., 8%) specified in JTG D30-2015.
* The temperature shrinkage coefficient decreased with the increase in temperature. The cement and solid waste in the stabilizer contributed to the hydration of the system. The formation of ettringit within the system caused volume expansion, reducing the harm caused by temperature shrinkage.
* The water stability coefficient decreased as the immersion time increased. Such a reduction could be mitigated by increasing the stabilizer dosage. When the stabilizer dosage of stabilizer A (30% cement content) reached 10%, the 90-day water stability coefficient was higher than that at 28 days.
* Quartz (SiO\({}_{2}\)), alumina (Al\({}_{2}\)O\({}_{3}\)), calcium carbonate (CaCO\({}_{3}\)), ettringit, and C-S-H were detected in the XRD analysis. When the stabilizer dosage and curing age increased, the intensities of ettringit and C-S-H became stronger. Soil particles covered by C-S-H, ettringit, and other hydrates could be observed in the SEM images.  
Conceptualization, H.L. and W.M.; methodology, S.Z. ([PERSON]); software, H.Z.; validation, K.W., Y.F. and S.Z. ([PERSON]); formal analysis, H.L. and S.Z. ([PERSON]); investigation, W.M.; resources, K.W.; data curation, H.Z.; writing--original draft preparation, H.L.; writing--review and editing, W.M. and S.Z. ([PERSON]); visualization, H.Z.; supervision, K.W.; project administration, Y.F.; funding acquisition, K.W. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the tsqn: 201909032.  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to the request of the Project Contract.  
Author [PERSON], [PERSON], [PERSON], and [PERSON] were employed by the company Shandong Hi-speed Group. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.