Table 11.  Maintenance and Rehabilitation Schedule for Pavement Alternatives Activities

 30

The applicability of the work schedule shown in Table 11 for the composite pavement 

with CRCP base alternative was verified using the distress prediction curves obtained in the 

technical analysis.  The curves were utilized to estimate the number of years required for a 

maintenance operation to be triggered because the corresponding distress reach the defined 

threshold (Figure 12).  The numbers of years for each analyzed distress to reach the threshold are 

summarized in Table 12.   

 

Table 12.  Years for Composite Pavement with CRCP Base to Reach Distress Trigger Levels 

Fatigue 

(Bottom-Up) 

Fatigue 

(Top-Down) 

 

Rutting 

 

Reflective Cracking 

 

Proposed Year for Maintenance Activity 

50+ 50+ ~11 

~8 

10 

 

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.E+00

1.E+07

2.E+07

3.E+07

4.E+07

R

u

t D

e

pt

h 

(i

n.)

ESALs (18,000 lbs load repetitions)

Granular

SC

CTB

Lean

RCC

PCC

~ 11 years

 

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

0

5

10

R

e

pet

it

ions t

o

 5%

 R

e

fl

ect

iv

e C

racki

ng on 

M

a

in

li

ne

Thickness of HMA (in.)

Soil Cement

CTB

Lean Mix

RCC

PCC

~ 8 years

 

Figure 12.  Estimates of Time to Reach Distress Trigger Values 

 

The proposed year for the maintenance activity (10 years) is within the range of the 

rutting and reflective cracking distresses presented in the table.  Although reflective cracking 

reaches an unacceptable level in 8 years based on the models used, it is important to mention that 

reflective cracking is highly unlikely due to the absence of longitudinal or transversal joints in 

the CRCP.  On the other hand, rutting in the HMA is more likely to develop, however, the 

milling and replacing of part of the HMA course every 10 years will correct the rutting before it 

reaches the unacceptable value.  Therefore, for the composite pavement with CRCP base the 10-

year functional maintenance frequency recommended by the literature was considered 

appropriate for the feasibility study.  The results of the LCCA are summarized in Figure 13.   

 

According to the LCCA, the least expensive pavement alternative was the composite 

pavement with a CTB layer.  The next least expensive alternative was the flexible pavement, 

which costs approximate 15% more than the least costly alternative.  The composite pavement 

with a CRCP base layer was the third least expensive alternative, costing approximate y 44% 

more than the least costly alternative over the life-cycle of the highway.  Finally, the rigid CRCP 

 31

had the greatest cost of all the pavement alternatives.  Several factors contribute to making the 

composite with CTB the least expensive alternative.  The unit price of the cement-treated 

aggregate (CTA), used to construct the CTB, is $21.00 per ton, whereas the unit price of a 

granular base (aggregate 21-B) is $18.00 per ton.  This suggests that the cost of the CTB and 

granular base layer is similar.  Because of this, the main cost is attributed to the HMA layer, 

which has an average unit price of $68.00 per ton ($76.00 for HMA surface mix, $65.00 for 

HMA intermediate mix, and $62.00 for HMA base mix).  The savings are due to the reduction of 

the typical thickness from 288 mm (11.5 in) for flexible pavement to 225 mm (9 in) for the 

composite with CTB.  

 

 

0.0 

0.2 

0.4 

0.6 

0.8 

1.0 

1.2 

1.4 

1.6 

1.8 

2.0 

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