Houstons source for info on custom decorative concrete, drivewayS, patios, Stamped/patterned concrete, admixtures for concrete. Also offer links to other related resources

Sunday, December 26, 2004

Building a Concrete Patio,Houston Patio,Concrete Patio,Pour Concrete,Concrete Patios,Paver,Sugarland

Building a Concrete Patio,Houston Patio,Concrete Patio,Pour Concrete,Concrete Patios,Paver,Sugarland
At Affordable Contractors we build a couple dozen stamped concrete
Patios and Stamped Concrete Driveways a month, countless square feet of
Foundations, Parking lots and sidewalks.

Over the years we've realized that the old adage' "They don't build 'em like
they used to" couldn't be more true about concrete Patios and Driveways.

About 90% of all the Driveways and Patios we tear out and replace have
wooden joints that rot and increase water intrusion potential, un-reinforced
concrete with about enough steel in the slab to make a nail or two and no
base, piers or compacted granular fill.

The staff here at www.ConcreteForever.com takes our hats off to all those
"They don't build 'em like they used to" concrete contractors because
without all of the shoddy concrete work done 20 years ago we wouldn't
have a job!

Twenty years from now however there isn't going to be a lot of Driveway and
Patio Replacements or Concrete Foundations to repair and you'll see why
after you read our Do it Yourself tutorial on "Building a Concrete Patio"

Sitework:
Establish a bench mark (elevation of slab) and fabricate batter boards at
the corners of the proposed concrete patio. The batter boards should be set
up with a builders level or transit and perimeter lines checked for a minimum
1/8" per ft fall for proper drainage. Install masonry string outlining the
perimeter of the outside edge of the proposed concrete patio.

Excavation:
Excavate approximately 10" down removing the soil from the area of the
new patio inside the strings, You'll need to bring in 2" of 3/4" gravel and
proportion the gravel to provide a average minimum compacted
compressive strength of a 80% compaction of uniform density and
thickness. Then, bring in 2" of a granular sub-base and machine compact
this sub-base to provide a minimum 95% compaction of uniform density
and thickness,to prevent potential sedimentary displacement and potential
thermal expansion.

Pre Soil Treatment:
After you've leveled off the granular base and reached your design
compaction parameters then you will need to treat the pre soil with
chlorpyrifos prior to installing a .006 mil vapor barrier.

Reinforcement:
Once this is in place then construct a "Central Grid Mat" using #4 steel
rebar every 12" -15" on center each way and "spin-tied" at each crossing.
Place the reinforcement grid on 3" rebar chairs. The rebar must not be any
closer to any surface (bottom, sides or top) more then 3" to alleviate
hydrostatic thermal expansion (ACI 318-02)

Optimizing the Correct Concrete Mix:
Ready mix concrete companies just bring out the concrete that you order
and they don't make any guarantees about anything. You are responsible for
the placing of the concrete and any cracks, settlement or discolorations are
the sole responsibility of the person that signs the delivery ticket.
For this reason it is important to hire an engineer or very experienced and
certified concrete contractor to engineer the concrete mix for your particular
application. In Houston Texas, depending on the humidity and barometric
pressure, the day of the pour we optimize the concrete mix with
variable proportions of tri-calcium silicate and bi-calcium silicates in terms
of performance variables, air entraining admixtures and fiber supplemental
reinforcement. The most important property is the compressive strength.
Cement particle-size distribution to strength development is a determining
factor assuming that the depth of the hydrated layer is independent of
particle diameter to quantitatively predict the effects of particle-size
distribution on strength evolution, which is an important factor influencing
compressive strength, with phase compositions becoming significant at
later ages.

Pouring the Concrete:
Fill the forms with the concrete making sure the steel reinforcement grid
stays centrally mobilized, Use an electric concrete vibrator to alleviate
potential voids around the steel grid and against the outer perimeter forms.
Screed the surface of the concrete with an aluminum 2"x4" beam that is
hollow, ( NEVER use a wooden 2x4 as it will flex and unevenly distribute the
concrete leaving an undesirable, untrue and "puddling" surface.

Floating the Concrete:
Once the concrete has been successfully screeded then, tamping the entire
surface with a "jitterbug" or "aggregate seeder" pushing the aggregate
approx 5/8" below the surface, thus optimizing the hydrating layer and
forcing the liquid cementious properties of the concrete mix to the surface
creating an optimum "top-coat". Then, using a minimum 48" magnesium
bullfloat, apportion the concrete evenly with the bull-float while another
simultaneously edges the concrete with an edger with a min 1/2" crown. As
the concrete hydrates the water is lost from the paste by evaporation or
absorption by aggregate, formwork, or subgrade which will further reduce
the reaction. If the internal relative humidity drops below 80%, hydration and
strength gain will stop. The rate of strength gained is directly related to the
amount of moist curing. The Maturity of the hydrating concrete mix is an
essential function of its temperature. Concretes of the same mix at the
same maturity have approximately the same strength, irrespective of the
actual temperatures experienced. A maturity meter is required to evaluate
the changes in temperature generated in the hydrating concrete, then apply
a mathematical formula to the measurements to calculate maturity.
Numerous mathematical formulas have been proposed for calculating
maturity, minimizing thermal stresses induced by the cooling of warm
concrete to cooler temperatures & the atmospheric pressure utilized to
increase the rate of strength development of the hydrating concrete. An
optimum temperature may range from 37.6 degrees celsius to 41.9
degrees celsius and is a compromise of strength gain and ultimate strength.
Now that the optimum temperature has matured the surface is ready to be
floated with either steel trowels, broom, lithochrome colors or stamped to
the desired texture.

article written by D. Hunt


"If you made it way down here then you must be spinning by now from all
the specs.....give us a call and we'll install your upcoming exotic concrete
patio at an affordable price!"



This site is updated daily at 8:00 p.m. GMT


Services
Pricing Form


Link to Us!

Concrete
Restoration


Calculate
Your
Concrete
Driveway
Cost


Exotic
Patio Bars



Polished
Concrete
Acid-Stain
Interior
Flooring

Free cost
analysis Form


Driveway
Designing
tips



Calculate
Your
Concrete
Patio Costs

Engineering
Services



History of
Concrete

Architectural
Concrete



Exotic
Driveways


Patio Bars
& Grills


Custom
WaterFalls


Custom
Concrete
Design
Studio

Architectural
Concrete
Walkways


Exotic
engraved &
acid stained
concrete
floors


Custom
Concrete
Colors



Office
Locations

Don't Click
Here!



Join our
Network


Concrete
Foundation
Installations


Concrete
Pricing
Update


Engineers &
Architects
Concrete
Variables &
Performance
Optimization
Tool


Building a
Cement
Driveway


No comments: