Some ideas on improvement in prestressing process are raised according to the observation and analysis on modulus ofelasticity, apparent yield limit, tensional strength and percentage elongation.
The results indicated that with the increase of the content of the extender oil, the tensile strength decreased, while the elasticity increased and elongation at break improved.
结果表明：随着填充油用量的增加，拉伸强度下降，弹性回复增加，断裂伸长率也增大。
3
Each root's maximum elongation ratio ranged from 50% to 70%, elasticity scope was 30-50 percent. Among C5-T1 roots, C7 root's maximum strength, elasticity were greater than that of other.