## 3 Results and Discussion
### Skid Resistance  
The BPN results for different fine aggregates to investigate the effect of micro-texture on RCCP skid resistance, as well as the effect of different macro-textures, before and after abrasion test are presented In Figure 17. The hypothesis is that the BPN is dependent only on surface micro-texture and represents low-speed friction [52]. The results of this study appeared different and show that the BPNs are more related to macro-textures. Based on the results of the two-way analysis of variance, different macro and micro-textures do not interact with each other, which means that in principle, two-way analysis of variance is not necessary to analyze the data, and each texture could be analyzed independently by one-way ANOVA analysis. Figure 16: The MTD of different mixing proportions and different macro-textures. Figure 17: The BPN of different mixing proportions and different macro-textures before and after abrasion test. The statistical analysis of two sets of BPN data before and after the abrasion test reveals that, based on the assumption of the level of 5 percent error, H0 is not accepted. In this case, the significant difference between these two sets is available, and the abrasion has a significant effect on the reduction in skid resistance. The difference between data averages is approximately 10 percent of initial specimens' BPN. One-way analysis of variance on each of the data sets of different micro/macro-textures separately to investigate significant differences in each data set reveal that changes in skid resistance in the form of BPN before and after abrasion is not significant for different micro-textures, while it is significant for different macro-textures. By comparing the percent results with previous studies that have considered micro-textures to be effective in changing the skid resistance, it can be pointed out that changes caused by macro-textures are much more than the values caused by micro-textures, and also the standard variations deal with micro-textures are widely so that the statistical analysis miss out their effects. Regardless of statistical analysis results and only by comparing different BPNs' mean, it can be claimed that in both before and after abrasion tests, the combination of 50-50 manufactured calcium and natural silica sand (Ca50 CSi50N) will create the best performance in terms of skid resistance. Grouping information using the Tukey method with the 95% confidence level reveals that BPN results categorized in two groups that one of them is consist of two types of brooming as well as small stamping macro-textures that have the best performance in skid resistance both before and after the abrasion test run on RCCP samples. In addition, the small seeding macro-texture has the worst performance. Results of different seeding macro-textures expressed that positive macro-textures may not be a preferred texture because the benefit of fine aggregate micro-texture is lost with washing out of the surface mortar. Investigation of various studies on the relationship between MTD and BPN [52; 53] and comparison with the results of this study showed that there is a strong relationship between the mean values for each type of macro-textures except brooming macro-textures with the average values of BPN. These relationships are plotted in Figure 18 for both before and after the abrasion test samples. Regardless of brooming macro-textures, the results showed that BPNs range after abrasion; vary approximately between 65 and 75. Analysis has shown that a maximum BPN with considering MTD threshold of maximum 15 mm is 70 that is effectively higher than the minimum threshold (42) expressed in different studies for high-speed roads to prevent accident [52]. In this study, no strong correlation was observed between the amount of abrasive mass with MTD or with the BPN separately. In fact, the mass worn depends on both the micro and macro-texture simultaneously.