Every evening, Wilmington daily commercial., 1922-01-17
the federal government has shared ex-
pcnse, Including state and local funds.
has been s4se.lsl.eSs. tho bureau an

Practically all forms Of modern
highway typos have been constructed
as provided under the various acts
sppropriatins Federal money, includ-
Ing vitrined brick. mscadam, sand
clay, aSpbsltic and cement concrete
and gravel. Altogether the mileage
built or approved has rcsched total
Of 2s.lsb.
In addition to exercising general
over Federal aid expendl-
lures, tho Bureau OF Public Roads Is
making scientific studies
OF pavement construction and behav-
Tor In order to make available to high
way engineers. public officials and the
public In general reliable and official
Information concerning modern high
way engineering practice.
These scientific studies are conducted
both Mt she government experimental
station at Arlington. and in the field
where the behavior OF highways In
actual use may be observed.
As an example Of the nature of>the
experiments conducted at the govern
ment station, can BIO. mentioned the
recent studies OF sub-soil conditions
end tho pavement over the sub-soil
witch studies revealed the fact that
concrete, pavements. for instance, curl
up anG down at the edges under the
heat Of che sun. Another instance
Of brick and concrete pavement speci-
mems 10 determine their sbility to
withstand impact or shock as It might
be impaired to them by the wheels
OF heavily loaded motor trucks.
In 1920 the bureau tentatively list
cording 70 their service value. based
on experience up to that time. in the
following order;
asphalt on concrete base; 3, cement
concrete; 4. bituminous concrete: 5,
bituminous mscadam; 6. surface
treated macadsm; Z, waterbound mac
adam; 6, gravel pacadam; 9, gravel;
| 10. sand clay.
bass were the only type specifically
listed at that time, the recent official
report on an investigation of rolled
| gravel, crushed stone and Stag bases
rointing out their service records and
length of life, and at the same time
emphasizing the availability Of the
material in territories where gravel
banks. stone auarries or supplies OF
Stag are located, contains conclusions
81 wide Interest. These conclusions
as quoted from the Official report, are
as follows:
THE study of these roads would
seem to warrant the following con.
illusions:
THAT the roiled-base type. provided
il is properly placed and compacted
is suitable type for brick construc
ton where soil conditions are favor
able and good natural drainage ma!
be obtained. Under these conditions
6-inch compacted rolled base shoult
be adequate, provided "a pinch san,
, or screenings cushion is used
5 THAT the rolled base may be sue
=. cessfulIy used under ordinary roa
conditions. provided the thickness O
/ tie base is adjusted to meet the prob
? able traffic requirements. An Sine
4 10 1o-inch compacted base with an ad
4 ditional inches of cushion Shout
, suffice under all but truckline high
!. ways subjected to very heavy trai
e fic.
: THAT whenever a rolled base
used bituiminous Father than a grol
g filler should be employed in order I
, provide flexible section Throughout
THAT in general asphalt filters III
/. more satisfactory than tar or tai
4 mastic filters. owing TO the tendency
= the latter either to chip out or flow
- hot weather. leaving the edges OF II
;. brick unprotected.
- THAT very inferior material, T,
=, measured by laboratory TESTS may
successfully used as base. material f.
:, brick roads.f
- Here is information Of much IN
:. portance and 1t especially applies
:. our State where read construction
now being carried on TO large e
tent. All practical information abo
road construction, therefore, is DO
interesting and valuable at this tin