**4. Conclusions**

It is a feasibility to produce entirely non-cement blended materials using S with FA and FA can be as an alkali activator for S in blended composites. In this study, we produced non-cement blended materials by replacing 100% of the cement (by weight) with S and FA at ratios of 4:6, 5:5 and 6:4. Specimens made with an S:FA ratio of 6:4 achieved compressive strength of roughly 30 MPa (at 28 days), which is the 80% the strength of conventional cement-based materials (control specimens). Non-cement blended composites were used to have a proper inclusion of fiber reinforcements to conduct the engineering properties and increase its applicability for construction applications. The inclusion of 0.2% fibers in the mix further increased compressive strength to 35 MPa. It also enhanced the compactness of micro pore-structures, increased the compressive strength and tensile strength and decreased absorption and the likelihood of shrinkage. SEM images and XRD analysis revealed that the compressive strength of the non-cement blended specimens can be attributed to the formation of C-S-H and C-A-S-H gels by Ca(OH)2, SiO2, and Al2O3. Polypropylene fibers were shown to have a profound effect in reinforcing the non-cement blended materials and it has shown the feasibility of the usage of non-cement blended fiber composites in civil construction.

**Author Contributions:** Methodology, W.-T.L. and A.C.; validation, K.K. and L.F.; data curation, J.C. and W.-T.L.; writing—original draft preparation, W.-T.L.; writing—review and editing, W.-T.L.; visualization, K.-L.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Ministry of Science and Technology (MOST) under the Grant MOST 108-2221-E-197-006 in Taiwan and the Czech Science Foundation under the project No. 19-11516S.

**Acknowledgments:** This research was acknowledged by the Polish National Agency for Academic Exchange under the International Academic Partnership Programme within the framework of the grant: E-mobility and sustainable materials and technologies EMMAT.

**Conflicts of Interest:** The authors declare no conflict of interest.

## **References**


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