## 2 Materials and Methods
### Laboratory Testing Methodology
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Material** & **Property** & **Value** & **Source** \\ \hline Confining pipe for grout annuli B, C & Yield strength & 240 MPa & Literature [42] \\ and D (ASTM A106 Grade B [42]) & Tensile strength & 415 MPa & Literature [42] \\  & [PERSON]’s modulus & 190-210 GPa & Literature [43] \\ \hline Confining pipe for grout annuli A & Tensile strength & 241–2450 MPa & Literature [45] \\ (ASTM A295 [44]) & Yield strength & 140–240 MPa & Literature [45] \\  & [PERSON]’s modulus & 183–213 GPa & Literature [45] \\ \hline  & [PERSON]’s modulus & 200 GPa (198.67 GPa) & Literature (Collected from tensile testing) \\  & Yield strength & 480 MPa (420 MPa) & Testing (from main laboratory investigation) \\ Rebar, \#6 Grade 60 & Yield strength & 480 MPa (420 MPa) & Literature [34] \\  & Tensile strength & 684 MPa (620 MPa) & Testing (from main laboratory investigation) \\  & & & [Literature] [34] \\ \hline  & [PERSON]’s modulus & 200 GPa & Literature [46] \\ Smooth bolt, 12L14 steel & Tensile strength & 504 MPa & Literature [46] \\  & Yield strength & 415 MPa & Literature [46] \\ \hline  & [PERSON]’s modulus & 12.5 GPa & Testing (1 sample unloaded and reloaded 3 times) 2 \\ Cement grout round 1 & Compression strength & 39.8 MPa & Testing (3 samples) 1 \\  & Poisson’s ratio & 0.24 & Testing (1 sample unloaded and reloaded 3 times) 2 \\  & Tensile strength & 1.64 MPa & Testing (1 sample unloaded) 3 \\  & Density & 1.91 g/mL & Measured (from 5 samples) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Summary of material properties. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Specimen** & **Grout Annulus** & **Rib Spacing** \\ \hline A-1 & & 14 \\ A-2 & & 27 \\ A-3 & & 41 \\ A-4 & 7.7 mm & 54 \\ A-5 & & 68 \\ A-6 & & Sanded smooth \\ A-7 & & Manufactured smooth \\ \hline B-1-i & & 14 \\ B-1-ii & & 14 \\ B-2 & & 27 \\ B-3 & 9.9 mm & 41 \\ B-4 & & 54 \\ B-5 & & 68 \\ B-6 & & Sanded smooth \\ \hline C-1 & & 14 \\ C-2 & & 27 \\ C-3 & 14 mm & 41 \\ C-4 & & 54 \\ C-5 & & 68 \\ \hline D-1 & & 14 \\ D-2 & & 27 \\ D-3 & 22.8 mm & 41 \\ D-4 & & 54 \\ D-5 & & 68 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Full laboratory parametric analysis of rib spacing and grout annulus. \begin{table}
\begin{tabular}{c c} \hline \hline
**Methodology** & **Percent Change in Density Compared** \\  & **to a Cylinder** \\ \hline O’Connor’s methodology [16] & \(-\)5.1\% \\ O’Connor’s methodology [16], with an additional & \(-\)8.5\% \\  & \(-\)8.5\% \\  & \(-\)0.1\% \\  & \(-\)0.1\% \\  & \(-\)0.08 \\ \hline \hline \end{tabular} \({}^{\dagger}\) Results are an average for 2 specimens selected randomly from rounds 2 and 3.  
\end{table} 
Table 3: Grouting methodology density comparison. The testing procedure for all the specimens was conducted in the same manner. This setup was very similar to other research conducted from our research group and aimed to simulate the anchorage length of the rock bolt in a similar manner to the methodology employed for in situ testing (ASTM D4435) [9; 49]. The specimens were set into the bearing rig, which can be seen in Figure 3. Then, the instruments were placed and it was verified that they were functioning. Load was applied via a Material Testing System (MTS) hydraulic grip using displacement control set to 1 mm/min. Testing was conducted until material failure was evident or a significant slip had occurred (<10 cm). Testing commenced with a verbal countdown and simultaneous start of the loading and all the data acquisition units (DAQs).