Research on a New Loading Method for Nano TiO2 Photocatalytic Asphalt Pavement
Round 1
Reviewer 1 Report
A well-documented manuscript with creation of new knowledge
Figure 1 (b)/not cited in text
Figure 7/legend SEP to replace with SEG
Author Response
Figure 1 (b)/not cited in text : the mistake has been corrected
Figure 7/legend SEP to replace with SEG : the mistake has been corrected
Reviewer 2 Report
This manuscript presents a new loading method of nano TiO2 photocatalytic particles with glass microbeads to enhance the effectivity of purifying car exhaust and its sustainability. The method is well described in this manuscript with detailed properties of the nano TiO2 photocatalytic particles and microbeads as well as specific loading process, which helps the readers to understand how the nano TiO2 is loaded on the microbeads surface. Verification of the effectiveness of the glass microbeads loaded with nano TiO2 (photocatalytic composite particle) is also well presented with the reasonable results of the light transmittance analysis. The most important part of the study is to find a way for the photocatalytic composite to exhibit its ability on the asphalt pavement surface as long as possible. The authors proposed a method of mixing the composite particles in the asphalt mixture itself and the slurry that fills the void of the mixture, which seems an excellent idea. The authors found the optimal depth of filling the slurry into the porous asphalt mixture to ensure the stability of the asphalt concrete. After that, they also found that spray embedding method is the best way to implement the photocatalytic composite on the semi-flexible pavement based on the persuasive results of the direct measurement of the degradation efficiency of automobile exhaust gas. Totally, the manuscript proves that the semi-flexible pavement with photocatalytic composite particle exhibits good efficiency of degradation of automobile exhaust gas in the laboratory level. The reviewer recommends the paper to be published in the journal. Furthermore, he wishes that this study be continued to verify that the same efficiency could be obtained in the actual service environment of asphalt pavements.
The following comments should be addressed:
Line 131. This sentence is not understandable to me. What does “the respectively” mean? Please check again.
Line 137. Seeing the Figure 2, “(a) and (b)” should be “(b) and (c)”. I can not see the peaks in (a) from the figure.
Author Response
Line 131, the mistake has been corrected
Line 137, the mistake has been corrected
Reviewer 3 Report
The research is very relevant and innovative, as it investigates an innovative aspect of nano-additives to reduce the negative impact of vehicles on the environment, i.e. provides a new idea for design of exhaust degradation pavement. However, the conclusions of the study are too general and numerical indicators are lacking. The research should include references to several more current sources, examples newer than 2018. In the introduction, it would be good to mention the actual pollution from road materials and their construction, as well as environmental impact assessment tool, for example, referring to the DOI: 10.3390/su132212487 to justify the ecological nature of the proposed solution. Then, logically arrive at the investigated solution and its predictable positive impact on the environment
Author Response
the recommendation has been adopted
