improve the sentense:

The LTOA 7D induces a much harsher age level than PAV 40h. PAV40h is shown to correlate generally to 8 to 12 years field aging [12, 37] while LTOA 7D aging in the current study is selected to mimic 12 years of field aging as previously mentioned. Also, NCHRP 09-54 reports PAV 40h agrees with 6 days of 95°C oven aging. 