1. Authors should include basis of selecting content of cement, i.e. 15 %.

2. Aspect ratio of PET fibres is quite high (greater than 150). Smaller length of PET fibres might have been more evenly distributed throughout the brick matrix leading to better reinforcement. The authors are requested to explain the basis of selecting such high aspect ratio of the fibres.

3. Hydraulic pressing stage is missing in Fig.4, whereas, the preceding para, i.e. lines 182-184 at page 5, speaks about employing hydraulic press. The amount of pressure applied may also be shared in text of the paper.

4. Fig. 6 (a) and 6 (b) presents images with 12000 X and 9000 X respectively. Line of scale at the right-hand bottom of the two figures distinctly shows the difference- 100  and 20  respectively. Comparison of microstructure can be better through micrographs of similar magnification. Authors are requested to include micrographs with similar magnification.

5. The observation quoted at line 355-356, page 10- ‘PET fibers, however, appear well-integrated within both PTR-A and PTR-D matrices, suggesting they effectively distribute loads, enhance crack resistance, and improve structural integrity’, is not visible in the Fig.6. Similarly, the observation quoted at the line no. 361-362 on the same page- ‘ but the incorporation of PET fibers in this study effectively mitigated these issues better’ is not clear from the test results/figures presented. Similarly, the two images of Fig. 6 seems insufficient proof for the observation made at line numbers 406 and 471-472 (pages 12 and 14 respectively): ‘microstructure of Fig. 6, where an increase in RHA (20 to 32 wt.%) increased the SEB porosity’ and ‘PTR-D also exhibited the most porous microstructure (Fig. 6b)’.

The authors are requested to include proper figure/s to substantiate the observations.

1. Alkali content of RHA as reflected by the data of K2O and Na2O presented in Table 3 indicates it to be ‘high’. The authors may include its effect on the hydration kinetics, if any. The authors may review literature on the possible expansion and cracking in matrix bearing cement/silica, due to high alkalis of RHA. The authors may also explore whether a little lower content of RHA than 20 percent may result in better performance than PTR-A in this light.

2. Age of sample of microstructure study is proposed to be added in section 2.3: microstructural characterisation. Fig. 6 (a) appears to show presence of : (i) partially hydrated cement particle/s (ii) hexagonal big crystal of portlandite and other forms of CH. Fig. 7 (a) also verifies CH in substantial amount in PTR-A. The authors may include further discussion on presence of these in the microstructure at the matured age and their possible significance on mechanical properties and durability of the bricks.

3. If the authors carried out particle size distribution (PSD) tests on TMS and RHA, then, are requested to include in the paper. The notion at line 387-388: ‘Residual quartz … contributing positively to particle packing’ may be explained with support of PSD.

4. Type of curing- immersion in water or spraying water etc. be please mentioned in the paper.
5. References may be added/quoted to support ‘delayed microcracking’ in presence of high content of RHA.
6. In the light of absence of quantitative test results about ‘porosity’ and ‘moisture retention’ , the lines 583-584 may be considered to be revised to :
   ‘PTR-D (45% TMS, 32% RHA, 8% PET) showed lower mechanical performance, though early-age strength was promising’.

Cement content is relatively high, justification provided is scanty.
Similarly, there is a need to investigate with RHA less than 20 %