ZH
EN
JP
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RU
DE?????????
?? 6??? ?????????? ??? ??? ??.
?? ???? ?????????? ??? ??? ??? ????: .
The American Road & Transportation Builders Association, ?????????
SCC, ?????????
AASHTO - American Association of State Highway and Transportation Officials, ?????????
- R 18-1993 ???? ???? ?? ?? ??? ?? ? ??? ?? ?? ?? ??(18?)
- R 18-1997 ???? ???? ?? ?? ??? ?? ? ??? ?? ?? ?? ??(19?)