全部

1·The frost crack rate of poplar plantation is above 60%.

杨树人工林冻裂率为60%以上。

2·Frost crack is the main failuve of asphalt pavement in permafrost region.

冻裂是多年冻土地区沥青路面的主要病害。

3·In the light of the above frost crack condition, the precautionary measures were put forward.

针对冻裂的具体情况，提出了今后的预防措施。

4·The experiment shows that poplar's frost crack could prevent by the measures such as white paint, wrapping grass, tending one time and reserving grass around tree trunk.

试验证明：对杨树进行涂白、包草和抚育一遍、树干周围留草可以预防杨树冻裂。

5·The frost heave and thawing settlement of frozen soil area can do great harm to the road and building which lies on it, such as the crack, settlement, fragile structures foundation element etc.

冻土区的冻胀、融沉给该地区道路和建筑物造成很大的危害，如使道路出现裂缝、沉陷、结构断裂、基础上拔等。

6·The properties of crack resistance, impact resistance, frost resistance and fatigue resistance of cement were improved by adding polypropylene fiber.

在混凝土中掺加聚丙烯纤维能有效地提高混凝土材料的抗裂性、抗冲击性、抗冻性能、改善混凝土的抗疲劳特性。

7·Frost boiling, alligator crack, net-shaped crack and pits are commonly found in highway pavement, they are resulted from the moisture damage in the asphalt concrete pavements.

沥青混凝土路面因水损害造成的唧浆、龟裂、网裂、坑洞等早期破坏现象，在公路路面中普遍出现。