## 6 Results
### Split Tensile Strength  
Test results and standard deviation and coefficient of variation of split tensile strength for all concrete samples are provided in Figure 3 and Table 7. Results overview demonstrates that recycled concrete aggregate is marginally detrimental to concrete tensile strength, while nylon fiber reinforced concrete has particularly more split tensile strength as compared to reference plain concrete sample. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Mix ID**} & \multicolumn{2}{c}{**28 Days**} & \multicolumn{2}{c}{**90 Days**} \\ \cline{2-5}  & **Standard Deviation** & **Coefficient of Variance** & **Standard Deviation** & **Coefficient of Variance** \\ \hline RCA0-SF0-PC & 0.550 & 3.568 & 0.208 & 1.366 \\ RCA50-SF0-PC & 0.737 & 4.860 & 0.436 & 2.750 \\ RCA100-SF0-PC & 0.7 & 5.691 & 0.450 & 2.847 \\ RCA0-SF20-PC & 0.929 & 5.943 & 0.351 & 2.351 \\ RCA50-SF20-PC & 0.438 & 2.803 & 0.577 & 4.570 \\ RCA100-SF20-PC & 0.346 & 2.220 & 0.458 & 2.975 \\ RCA50-SF0-NFRC & 0.945 & 6.329 & 0.754 & 4.689 \\ RCA50-SF0-NFRC & 0.404 & 3.224 & 0.450 & 2.841 \\ RCA100-SF0-NFRC & 0.655 & 4.285 & 0.680 & 4.497 \\ RCA0-SF20-NFRC & 0.490 & 3.129 & 0.503 & 3.921 \\ RCA50-SF20-NFRC & 0.305 & 1.941 & 0.358 & 2.314 \\ RCA100-SF20-NFRC & 0.828 & 5.383 & 0.929 & 5.943 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Standard Deviation and Coefficient of Variation of Split Tensile Strength (MPa). Figure 2: Relative Analysis of Compressive Strength. No major variation in split tensile strength was observed when amount of recycled concrete aggregate is increased from 0% to 100%, contrasting to compressive strength, recycled concrete aggregate does not have any adverse effects on split tensile strength. This could be attributed to the difference in failure under split tensile and compression loading. In compression, recycled concrete aggregate increased dilation could increase sample lateral strain, which prompts rapid failure. Past researches [54] has revealed comparable studies. Authors in writing [26] reported that in a test of split tensile, in natural aggregate concrete failure plan passed through ITZs amid new cement paste and natural concrete aggregate demonstrating poor bond, while, in case of RAC failure plan passed well in the recycled concrete aggregate. Figure 3: (**a**) Split Tensile Strength (**b**) Split Tensile Strength of Each NFRC Mix W.R.T Plain Concrete (PC). concrete aggregate. ITZ failures in the case of natural aggregate concrete could need more split tensile load as compared to trans-aggregate in the case of recycled aggregate concrete. Hence, natural aggregate concrete displayed a more split tensile load as compared to recycled aggregate concrete. For a given dose of recycled concrete aggregate, at 28 days of curing silica fume does not affect the split tensile strength majorly. At 90 days of curing, samples with silica fume did well as compared to the concrete sample with no silica fume. Silica fume ascribed more to the gaining of strength in the case of recycled aggregate concrete than natural aggregate concrete samples. By reacting at the ITZ between RCA old mortar and cement paste matrix, leads to improvement of RCA split tensile strength. It can be concluded that concrete samples having silica fume did well (4-6%) as compared to the reference control sample (RCA0-SF0) at 90 days of curing, it can be seen in Figure 3. Recycled aggregate concrete samples having silica fume also performed better as compared to natural aggregate concrete having silica fume. Nylon fiber leads to a notable rise in split tensile strength. Nylon fiber reinforced concrete samples have a major margin of 15% over reference control samples, it can be seen in Figure 3. Concrete samples in the presence and absence of silica fume, exhibit a prominent rise in split tensile strength. As compared to 28 days cured concrete samples, nylon fiber reinforced concrete samples display gain more split tensile strength at 90 days of curing.