导致预制铺路砖表面凹凸不平的因素很多，包括在行人路上违例泊车，以致路面负荷过重； 铺砌方法不当； 以及掘路后进行的修复工程不合标准等。

There are many factors which contribute to the uneven surface of precast paving slabs. this may be due to the heavy loading caused by illegal parking of vehicles on the footway ;

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金属以及其它不能转化为气体的无机材料会落在密室的底部，成为熔渣，冷却下来可以用来作砖或铺路。

Metals and other inorganic materials that do not turn into gas fall to the bottom of the chamber as molten slag. Once it has cooled, this slag can be used to make bricks or to pave roads.

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一旦冷却，这种熔渣就可以用来制砖或者铺路。

Once it has cooled, this slag can be used to make bricks or to pave roads.

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一旦冷却，这种熔渣就可以用来制砖或者铺路。

Once it has cooled, this slag can be used to make bricks or to pave roads.

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