macadam pavement
2.(3)The geograph y distribution of the road γ radiation dosage is similar, i．e:the middle moun tain area in the North is highest,the low mountain area in the Southeast and the East are the second．The river valley and flat land area in the Southwest is lo west．(4)The land γ radiation dosage rate of different road pavement is in sequ ence:clay road＞macadam road＞brick road＞tar road＞cement road．
