Goliad County Solves Basic Problem
with Simple Solution
By Donald H. Taubert
Director, Promotion & Technical Service
Capitol Cement
  Ted
Long, Construction Foreman for Goliad County in South Texas, recently
solved a distressed pavement problem with portland cement. During
a routine road examination earlier in the year, Long noticed some
"soft spots" on Manahuilla Road, in northwest Goliad County.
There were several options for repair, including removal and replacement
of the base and asphalt surface, patching soft spots, or recycling
the entire base and pavement with portland cement, a more durable
and economical repair technique. Long chose the recycling because
it did not require removal and disposal of the road bed materials.
All the materials are recycled in place, hence no hauling and disposal
costs are necessary.
Portland
cement works to stabilize all kinds of base materials found in Texas.
It binds and hardens caliche and pit-run materials as it creates
a soil-cement base for the surface course. It can also be used to
create a permanent working platform by stabilizing granular and
plastic soils underneath. When the failed flexible pavements are
pulverized, mixed, and compacted with cement, the mixture provides
a road base with strength and long-lasting durability. The process
is simple. The surface is scarified to a depth of six to eight inches,
and portland cement is placed over the surface at the prescribed
amount and blended with standard mixers.
 The
project on Manahuilla Road required twenty-three pounds of cement
per square yard, six inches deep (about 4.5 percent by weight of
material). Goliad County doesn't have a rotary mixer, so their experienced
motor-grader operator did all the blending and mixing. This was
the same process that was used in projects that were built in the
U.S. as early as 1938.
After the mixing, the material was bladed off to
the shoulder and then placed back on the roadway and compacted in
two lifts using normal watering to achieve optimum moisture. The
base was compacted to standard density with tractor drawn pneumatic
and sheepsfoot rollers. The road stayed 18 feet wide, but shoulders
were added with this "new" base material.
 "Pre-cracking"
is a new technology recently developed that inhibits typical soil-cement
crack patterns that might reflect through the asphalt surface. The
following day, Long rolled the completed road base several times
with the pneumatic roller to induce "micro-cracks", which
ultimately prevent reflective cracking yet maintains the base's
structural integrity. He also rolled the roadbed one to two hours
before seal coating. Bad weather and holidays prevented the county
from shaping and crowning the road for several days, but Long felt
that the situation did not cause a problem.
The
road was chip-sealed with CRS-2 oil at 0.45 gallon per square yard
and PB4 natural asphalt rock for chip seal at 120 tons per mile.
The entire process was then repeated for a second coat, ensuring
a durable surface treatment.
 Long
said, "I like that fact that we were able to complete this
repair with portland cement at less than one half the cost of usual
procedures. I also feel that we now have a better product than we
would have had by adding additional or even other base material
to the existing pavement without a stabilizer, as we have done it
in the past. We were also able to do it with our own road crew."
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