| Title |
Shrinkage Crack Control of Hwangtoh Mortar using Fiber and Admixture |
| Authors |
Mun Ju-Hyun ; Yang Keun-Hyeok ; Jeon Joong-Kyu ; Hwang Hye-Zoo |
| Keywords |
Hwangtoh Mortar ; Fiber Reinforcing ; Unrestrained Drying Shrinkage ; Restrained Drying Shrinkage ; Plastic Shrinkage |
| Abstract |
A total of 8 hwang-toh mortar mixes with no cement were tested to evaluate the effect of different fibers and admixtures on the control of shrinkage cracks of such mortars. The fiber types added were Lyocell, Poly-Amid and PVA, while, CSA and organic polymer were selected as the admixture. The shrinkage crack resistance of hwang-toh mortar were examined from the unrestrained drying shrinkage strain, restrained drying shrinkage and plastic shrinkage. Test results revealed that the unrestrained drying shrinkage strain of hwang-toh mortar sharply increased at an early age showing approximately 2.5 times higher values than predictions obtained from ACI 209, regardless of the addition of fibers and admixtures. In addition, cracks owing to the restrained drying shrinkage developed at the only age of 1.6 days in all test mixes; as a result, the cracking grade of hwang-toh mortar was evaluated to be high. On the other hand, the addition of fibers required a value of fiber spacing above 0.0003 in order to enhance the tensile resistance capacity of hwang-toh mortar under the restrained drying shrinkage and reduce the cracking area under the plastic shrinkage. Overall, it could be concluded that moist curing at an early age and the addition of fiber with fiber spacing above 0.0003 are practically effective in reducing shrinkage crack of hwang-toh mortar. |