Los Angeles herald., 1909-12-19

proving of matters yet remaining are
the selection of suitable location for
securing an ample quantity or rock
and the early grading of all ROADS
which are to be macadamized next
summer.
"I am informed that the quarries at
San Dimas and Pacoima contain an
ample quantity of suitable material
for rock, but I have not yet been able
to visit these quarries to make a per-
sonal examination of conditions.
"As to the grading of the roads
which are to be macadamized in the
near future, these matters are entirely
in the hands of the highway commits
sion and it's engineers, and 1t is their
duty to extend this work during the
winter season as much as possible.
"Roads graded during the rainy sea-
son will settle and be in good condition
for surfacing in the spring.
recommendations
"In concluding this report, 1 will
make a few recommendations which
seem to be warranted by examinations
made up to this time:
"Flrst-Natural oil should never be
used for bonding macadam road work.
because the substance is too volatile
and contains constituents which are
mere waste and would not impart ben
eficial results to the work.
"In place of natural oil, a residuum
from refining petroleum having an as
phalt base should invariably be en-
ployed. The fixed bitumen in the oil
Is essential, as the constituent which
makes a permanent and strong bond
in the macadam, and residuum with
as much bltumen as possible should be
employed for making bonded macad-
ans. 1t will be more difficult to apply,
and would require a high degree of
heat in order to secure proper pene-
tration, but the results of the work
will be so much more satisfactory and
the roadway of such great perma-
nency as to fully warrant the extra
expense and trouble.
"Second-None but hard rock and
screenings from same should be used
on the roadway and sufficient residuum
used to fill all the voids In the rock
and screenings. If penetration cannot
be secured by laying the rock In two
courses, as required by the present
specifications, 1t should be laid in as
many courses as necessary to properly
fill the Voids. The voids or interstices
from the bottom to the surface of the
macadam should be bonded with as
phaltum as fully as possible, since it
has been shown that the only kind of
TOduWdy WHICH Will permanently WIN
stand high speed motor vehicle traffic
must be made in this manner.
protected macadams with a thin
cover or skin of oil become wavy under
the action of automobile traffic. / dis
cussed these matters with Mr.. Loder,
and he has the correct idea in regard
to a bonded macadam being the most
satisfactory, but 1t is unquest,onably
true that the specifications now In use
are not sufficient for obtaining a sat-
isfactory bond for the reasons I have
given.
I'm conclusion, / desire to thank Mr..
Loder and his chief assistant. Mr..
Slemons, for their desire to give me
all the information at their disposal
and facilities for making personal in
vestigations. These gentlemen are both
earnest and competent engineers, and
their work has been conducted along
good engineering lines with such ex-
ceptions as l have herein above noted.
The highway engineers claim that all
work now done is we'll within the
original estimates of cost. AS to this,
/ will advise you in a future report
after thoroughly investigating the
matter"