dc.description.abstract | Abstract
Directorate General of Highway continues using the 1958 edition
of ”Highway Construction Technical Provision” published by Ministry of
Transportation and Communication (MOTC)as a guide of pavement
construction now and before. In this technical provision C-3 grade coarse
aggregate and D-3 grade dense aggregate are served as the applied
specifications of aggregate used in Asphalt Concrete mixture.
It is necessary for Directorate General of Highway to amend its
paving material specification in order that all the correlated quality of
paving material should conform to the 2001 edition of ”Highway
Construction Technical Provision” revised by MOTC. Therefore, the
Material Testing Laboratory Office of Directorate General of Highway
advise that adopting Table 3-21 (Type-I Dense Grade Aggregate)and
Table 3-23 (Type-II coarse grade aggregate utilized in base course)
specified in this 2001 edition technical provision to amend specification
of aggregate used in Asphalt Concrete mixture, and by means of Test
Road Review to trace its long-term performance and to evaluate
performance of these new grade asphalt concrete,so as to get a step
further to review whether this new Technical provision fit in with the
requirement of Directorate General of Highway in its working out
highway pavement construction.
Through an evaluation of test road, the collected data have verified
that aggregate produced from Taiwan area can fit in with these new grade
asphalt concrete, and the correlated contractors who take charge of
highway pavement construction are capable of producing asphalt concrete
mixture conforming to this new standards.
For avoiding bleeding defect of asphalt concrete pavement occurred
in high temperature area, the quality control factor of asphalt content is
much more important, and better asphalt content is not so much existing
at a point as distributing in an area. Also some high viscosity grade
asphalt can be selected to serve as binding material of asphalt concrete
mixture.
While manipulating construction in practice, the correlated
regulation specified in asphalt concrete part of 1997 edition “Technical
specification of highway construction” revised by Directorate General of
Highway can still be consulted to. But in the phase of production quality,
we should pay attention to 25mm coarse grade aggregate and 25mm
Dense Grade Aggregate stated in this new standard. Mix plants are likely
to ignore the quality control of 25mm sieve Aggregate in use, and tending
to produce a fine grade deviating phenomenon in asphalt concrete
mixture, because 25mm grade aggregate is not prevailing in Taiwan
asphalt concrete market so as to result in an influence of quality referring
to asphalt concrete mixture.
The result of Test Road performance evaluation is good in substance,
but there is no apparent difference while comparing with the original
standard of asphalt concrete in their initial performance owing to the
evaluation last only one year. Therefore, it is suggested that the
performance tracing should be continued so as to build up long term
performance data and find out its benefit more accurately from Test Road.
To sum up then, this new standard asphalt concrete can widely be put to
use in the area under management of Directorate General of Highway;
and it is very helpful for Directorate General of Highway to acquire
favorable public impressions and raise highway construction quality up to
pavement serviceability. | en_US |