Evening journal. [volume] (Wilmington, Del.) 1888-1932, 1917-05-24
TWENTY MILES OF Dupont BOULEVARD PRESENTED TO THE STATE TO-DAY

,tal to others In the field il was noted
that as the amount OF lime was in
creased, up to 10 per cent, the per-
centage Of transverse cracks was re-
duced Disregarding the slight in.
crease or decrease of strength in the
concrete due to the hydrated lime, il
seems 10 assist in the construction
by making the concrete flow more
freely and preventing segregation OF
the coarse aggregate. II is possible
that the hydrated lime assists the
prevention Of transverse cracks. in
ASA .ch as the lime-cement concrete
retains moisture longer and thus does
not contract as much during the first
"a or 4S hours while the concrete Is
getting strength. a period that starts
the greater number OF the transverse
cracks
Allowed For Expansion.
During the early spring when the
concrete was saturated and thus ex
banded and when the expansion was
az its maximum due 10 the tempera-
ture. a number of the slabs rose at
the joints causing an abrupt uneven
ness The greatest rise was / IA ms.
After the concrete became dried out
nearly all OF these slabs return to
! their original positions. This uneven
condition was not observed at a sin.
( gle crack; therefore. Il was decided
| TO no longer restrict the length OF
I slab but to make It as long as pos
sible
Nearly all joints we're protected by
protection plates This was found TO
be a decided advantage during the
I spring while one slab was slightly
above the other, for when the trafic
hit the higher slab the plate would
protect the edge OF the concrete from
abrasion Some joints were made OF
bituminous filler only. while some
we're butt joints having no filler or
plate. A few OF the slabs having the
butt joints were reinforced across the
joint with steel rods. This keeps the
joint from opening and gives It the
appearance OF a fine crack. Where
this was done the resulting slab was
24O II. iR length
1T IS difficult to decide whether OF
not the reinforcement used has beer
an economic advantage. IL Is claimed
\ by the manufacturers Of paving rein
Iforcement that the reinforcement doe
not prevent cracking, but II does pre-
vent the cracks from opening. Thi
may be true during the greater par
OF the year. but in the fall after
continued dry spell and when tn
, temperature suddenly drops the rein
forccment does not prevent the open
ing OF the cracks, especially in tn
longest slabs. II all the slabs wer
short the reinforcement would VI
doubtedly prevent the cracks fror
opening. More time is necessary j
orders to thoroughly study the aC
vantage OF reinforcement under thes
/, conditions. While the smaller exper
, monts Indicate that reinforcing n
! duces the number OF cracks. the lars
! or experiments do not seem to confrr
! this.
: Complete Record Of Construction.
Daily records OF all materials use
= and methods followed we're sent {
[, the main office. where they wer
q tabulated on large charts. BY thl
=, means a complete record OF all tn
II construction has been kept. Thes
~ charts show the kind OF material
~ used. the proportions and the met
"a DDS in which It was used: the natul
,s and condition of the subgrade; drai
= age: the number Of bags OF cemei
~ used etc, and also the maximum an
"a minimum temperatures for the day
N "The testing engineer complete
20 these records by taking samples
a the materials and testing them. chic
~ TO insure their quality, but also
make the records complete. The II
= spectiOn was thorough and carried o
I, by capable men of wide experienced
% To the inspection and testing Of ms
y terials Is due the credit for the es
I, oellent work that has been done
= THE next section of the duPon
y road will be extended in a northerl'
u direction 10 the town OF Milford Thii
Y will complete the DUPONT road in Sus
sex county and will mean that more
I than one-third Of the road has beer
constructed through the entire state.