334 Table 13 – Viscosity (Zahn cup and dynamic), density, and gel time results for colloidal system A Colloidal system A Test Design No. Zahn Viscosity (s) Dynamic Viscosity (cP) Density (kg/L) Gel Time (min) Test 1 1 33.71 4.76 1.09 69.15 Test 2 1 33.75 4.80 - 65.12 Test 3 2 33.41 4.45 1.09 48.17 Test 4 2 33.5 4.55 - 50.25 Test 5 3 33.07 4.11 1.09 29.13 Test 6 3 33.09 4.13 - 30.36 Table 14 – Viscosity (Zahn cup and dynamic), density, and gel time results for colloidal system B Colloidal system B Test Design No. Zahn Viscosity (s) Dynamic Viscosity (cP) Density (kg/L) Gel Time (min) Test 1 1 32.95 3.99 1.18 70.10 Test 2 1 32.92 3.96 - 66.89 Test 3 2 32.81 3.85 1.18 59.21 Test 4 2 32.79 3.83 - 54.10 Test 5 3 32.74 3.78 1.18 37.24 Test 6 3 32.69 3.73 - 40.22 The acrylamide-based system showed initial viscosities closest to that of water (water viscosity approximately 2 cP), associated with its high aqueous fraction and the absence of a solid phase prior to polymerization. Colloidal silica systems exhibited slightly higher viscosities, attributable to the presence of suspended silica nanoparticles, while remaining fully compatible with fine grouting applications. Acrylic resins showed moderately higher viscosities, particularly in formulations with higher monomer concentrations, without compromising injectability. Measured densities ranged between 1.03 and 1.18 kg/L, being lower for polymeric systems and higher for colloidal systems, consistent with the presence of nanometric solids. These differences may influence fluid stability during injection and behavior under hydraulic gradients. Regarding gel time, all systems demonstrated a high degree of kinetic control. The acrylamide system achieved gel times ranging approximately from 45 to 86 minutes, evidencing a wide workability window and marked sensitivity to retarder dosage. Acrylic resins generally exhibited shorter gel times (26– 45 minutes), with greater dependence on temperature and the activator-to-initiator ratio. In colloidal silica systems, increasing NaCl concentration progressively reduced gel time from values exceeding 70 minutes to approximately 30 minutes, reflecting a gradual gelation mechanism driven by ionic destabilization. 5.3. Behavior in the Hardened State The behavior in the hardened state showed clear differences among the families of materials evaluated. Colloidal silica systems developed a homogeneous, rigid, and dimensionally stable gel structure, attributable to their mineral nature and to the formation of a continuous three-dimensional network of silica particles. This behavior is favorable for permanent waterproofing applications.
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