First, I would like to thank you for sharing your research activities/outcomes time to time. I found them really interesting and gain useful information.

Today I am writing you as you provided an opportunity to comment on the website directly.

I like this study because of a simple yet unique idea of measuring the crack growth. Certainly, the colloidal silica admixed specimens outperformed the control specimens as evident from its dense, compact and uniform matrix, however, it would be interesting to support the results from mineralogy or bond characteristics from XRD and FTIR analysis, respectively. I would like to know if the SEM analysis was carried out on paste specimens or the fragmented mortar specimens after the compression testing? Because sand is an inert material, I believe that the microstructure of paste specimens should be compared.

Best regards
Muhammad Nasir, PhD
Lecturer, Civil and Construction Engineering Department
Imam Abdulrahman Bin Faisal University, Saudi Arab