Question

Example 2. The Navy is building a road at a new installation. Pavement base coarse specifications require that the compacted soil must be at least 0.95 Y dima) With moisture content 2% of wopt. The desired base coarse soil was laboratory tested for specific gravity and compaction; results are compiled in Table 1. After compaction of the soil in the field, nuclear density control tests were conducted at five separate locations. The results of the control tests are shown in Table 2. Perform the necessary calculations to see if the field compaction meets the specifications. Plot your compaction results (Ye Vs. w) as a comprehensive compaction chart. Comment on the validity of the lab and field tests Table 1. Lab compaction test results Moisture Dry unit wt. Zero air void Ye (kN/m3) Y(kN/m3) Table 2. Field compaction test results content Moisture Moist density p (kN/m2) w (6) zav Location content 11 15.92 20.35 w(%) 13 16.74 19.54 1 14.67 2062 15 17.10 18.79 2 15.82 1978 17 17.21 18.10 3 16.41 1954 19 16.91 17.46 4 17.57 1970 21 16.64 16.86 5 19.70 2198 Specific gravity (G,) = 2.69

Answer 1

Ans)

wwe s as Altonaing to lab tet data, mpaction 19 MoD=.25 KNhn? 16 15 onC =17% +> 20 5 Molstuwu eritint Col.) 15 10 D.y Dansity Ckh Ln

From above compaction curve .

Optimum moisture content (OMC) = 17 %

Maximum dry density (MDD) = 17.25 kN/m³

For field test data we have to first calculate dry density :

Dry density = Moist density / ( 1 + W) , where W = water content

Below table contain dry density calculated using above formula :

Location	Moisture content (%)	Moist density , $\rho$ (kN/m3)	Dry density,$\rho$d (kN/m3)
1	14.67	20.62	17.98
2	15.82	19.78	17.07
3	16.41	19.54	16.78
4	17.57	19.70	16.75
5	19.70	21.98	18.36

Required compacted soil = 0.95 x 17.25 = 16.38 kN/m³

Required water content = 17 $\pm$ 2 = 15% - 19 %  

For location 1, $\rho$_d = 17.98 and W = 14.67% , water content is less then required

For location 2, $\rho$_d = 17.07 > 15.82 , soil meets requirements

For location 3, $\rho$_d = 16.78 and W = 16.41 , soil meets requirements

For location 4, $\rho$_d = 16.75 and W = 17.57 , soil meets requirements

For location 5, $\rho$_d = 18.36 and W = 19.71 , moisture is more than required