抄録
In a previous paper, the authors reported on experiments on farm road pavement using a tar mixture. This paper deals with pavement of farm road using an asphalt mixture and a tar mixture, and deals with properties of the subgrade of farm road. Thepaving methods were as follows;
(A) Asphalt Concrete (Coarse Graded)
(B) Tar Concrete (Coarse Graded)
(C) Tar Concrete (Coarse Graded) with Canvas
(D) Surface Treatment with Tar.
Soil moisture meters (plaster block) and thermistor thermometer were used in order to measure soil moisture and temperature in the subgrade. Earth pressure cells were buried in the subgrade for measurement of earth pressure under a traffic load, and CBR test and Proof-rolling test were carried out after paving to measure the bearing capacity of the farm road. Results show that properties-soil moisture, soil temperature and earth pressure-of subgrade under pavement are different from that which is not paved. The soil moisture of road which has notbeen paved show a large change when compared with that.Lader pavement. The soil temperature near the road surface is higher than that in the inner part in summer and on the contrary lower in winter.
In regard to earth pressure under traffic load, it was indicated that the pavement have a dispersion effect of earth pressure.
Finally, CBR of the subgrade was measured. As a result, it was indicated that CBR is affected by water content and a relation between CBR and water content of subgrade is indicated.
In general, it was shown that pavement of farm road has a good affect upon the subgrade and paving methods (A) and (B) are suitable for farm road pavement.
