| Title |
Strength Variation of Cemented Sand Due to Wetting |
| Keywords |
cemented sand;unconfined compressive strength;wetting;고결모래;일축압축강도;수침 |
| Abstract |
In this study, weakly cemented sand was cured at air dry condition with different periods (3, 7, 14, 21, 28 days) and its unconfined compressive strength was evaluated. As a result, the strength of specimens with low cement ratios such as 4 and 8% increases until 7 days curing but, after 7 days, their strength continuously decreases. The strength of specimens with relatively high cement ratios such as 12 and 16% increases up to 7 days curing and then stays almost constant until 21 days. After 21 days curing, their strength suddenly dropped down, which is much lower than the strength of 3 days curing specimen. A cemented sand and gravel called CSG, which is highly permeable, could be exposed to repetitive drying and wetting conditions due to rainfall or groundwater table change during curing. In this study, the weakly cemented sand is exposed to repetitive drying and wetting and then its unconfined compressive strength was evaluated. As a result, the strength of a specimen with 27 days drying condition following 1 day wetting was at maximum 35% lower than the one cured under 28 days drying. The strength degradation due to wetting decreases as a cement ratio increases. However, the strength of a specimen with repetitive drying and wetting increases as the number of wetting increases until 3 cycles. After 3 cycles of drying and wetting, the rate of strength increase decreases due to an insufficient water for hydration or stays constant. If the sufficient water supply is provided to cemented sand during curing, the target or design strength increase can be achieved. Otherwise, the strength degradation due to wetting should be considered at the design stage. |