132 
PARK AND 
CEMETERY. 
77th ST.: PORTION RIVERSIDE 
DRIVE, NEAR SOUTH END; BINDER AND 
SAND TREATMENT. 
WEST DRIVE, CENTRAL PARK, NEAR 
TO BE PAVED. 
concrete gutter. The former gutter, 
which is hidden by the edging stone, 
is about 1 in. below its top and does 
not show in the illustration. 
One effect of the continual addition 
of new material on the drives has 
been to raise the road surfaces con- 
siderably above the level of the ad- 
jacent ground and to produce exces- 
sive crowns. This is particularly no- 
ticeable at certain places, as is shown 
in one of the accompanying illus- 
trations of a portion of East Drive 
near the 59th St. entrance to the 
park. Another undesirable feature of 
this method of resurfacing has been 
that as the level of the roadway 
has been raised the gutters have been 
rendered useless and new ones have 
had to be built at the new levels. 
Many of the original gutters were of 
rubble and were at first replaced with 
asphalt blocks. The later practice 
has been to use concrete. 
A surface of ordinary gravel being, 
of course, inadequate to the require- 
ments of traffic such as that to which 
the park drives are subjected, it has 
been necessary to adopt some means 
of providing a more suitable surface. 
Up to the present time this has been 
done by the construction of a bitumi- 
nous carpet over the surface of the 
drives. This surface has been built 
up by applications of bituminous ma- 
terial and sand, and varies considera- 
bly in thickness. On a portion of 
East Drive in Central Park a section 
of this carpet taken up had a thick- 
ness of about in. 
Last summer Riverside Drive from 
75th St. to 129th St. was resurfaced 
with this material, and early this 
spring the lower section from 72d St. 
to 90th St. was reconstructed, as well 
as large patches between 90th and 
129th Sts. Above 129th St., running 
north to 155th St., the road was re- 
constructed, but no binder was used. 
In Central Park all of East Drive, 
from 59th to 110th St., as well as por- 
tions of West Drive and all of Middle 
Drive from 59th to 72d St., was treat- 
ed with asphalt binder during 1911. 
At present the force is working on 
all drives other than that portion of 
the West Drive between 66th and 102d 
Sts. that is to be laid with a perma- 
nent pavement under contract. 
The bituminous material is pur- 
chased under specifications by the 
Department of Parks, received in tank 
cars and applied by sprinkling wagons 
by day labor. 
The specifications for the bitumi- 
nous material are as follows: 
1. It shall be free from water or decom- 
position products. 
2. The various hydrocarbons composing 
it shall be present in homogeneous solution 
no granular constituents being present. 
3. The gravity at a temperature of 60 
degrees F. shall not be lighter than 12.5 de- 
grees Beaume. 
4. The asphalt contents of 100 penetration 
at 77 degrees F. after evaporation in the 
open air at a temperature not exceeding 500 
degrees F. shall not be less than 90 per 
cent. 
5. Twenty (20) grams of it upon being 
maintained at a uniform temperature of 325 
degrees F. for 5 hours in a cylindrical ves- 
sel 2% ins. in diameter by % in. high shall 
not lose more than 1 per cent in weight. 
6. Twenty (20) grams of it upon being 
maintained at a uniform temperature of 400 
degrees F. for 5 hours as stated above shall 
not lose more than 3 per cent In weight. 
The character of the residue at 77 degrees 
F. shall be smooth and nearly solid, but not 
so hard that it may not be easily dented 
with the finger. 
7. It shall be soluble in chemically pure 
carbon disulphide at air temperature to the 
extent of at least 99 per cent. 
8. It shall be soluble in 76 degree Beaume 
petroleum naphtha, air temperature, to the 
extent of not less than 88 per cent. 
9. It shall show an open flash point of not 
less than 400 degrees F. 
10. The material shall be furnished as 
required by the Department in carload quan- 
tities and shall be delivered in tank cars by 
railroad at Hudson River and 79th St. or 
96th St. in the Borough of Manhattan, as 
may be directed. 
President Charles B. Stover, of the 
Park Board, Commissioner of the De- 
partment of Parks of the Boroughs 
of Manhattan and Richmond, and the 
engineers of the department have de- 
voted considerable time to investigat- 
ing the problem of providing pave- 
ments for the park roads which will 
be most suitable for the traffic which 
they have to carry. During 1911 sev- 
eral short experimental sections were 
laid, most of them being of bitumi- 
nous macadam or concrete, some on 
macadam foundations and some on 
Portland cement concrete founda- 
tions. The observation of the exper- 
imental sections, and the study of 
the conditions and needs have led to 
the conclusion that the best results 
can be secured by the construction of 
a concrete foundation on which is 
placed a bituminous wearing surface. 
It is believed that the deep layer of 
gravel now making up the roadbeds 
of the drives will provide an excel- 
ent sub-foundation for the concrete, 
so that the concrete when put down 
will, to all intents and purposes, be 
permanent. A pavement of this na- 
ture is soon to be laid on West Drive, 
between 66th and 102d Sts., bids for 
the work having been received on 
May 23. The total area to be paved 
is about 51,000 sq. yds.; the concrete 
foundation will be 5 ins. in thickness 
and will contain about 7,000 cu. yds. 
of concrete. The plans for the work 
contemplate the excavation of 14,000 
cu. yds. of the old gravel roadway. 
The wearing surface will be laid 
under the following specifications: 
Wearing Surface. — After the concrete foun- 
dation has been deposited as above described, 
and has reached its proper set, there shall be 
laid over the surface of the same and evenly 
