specs

Section 03300
Page 5
D. Documentation of Average Strength: provide evidence of average strength for each class of concrete in
accordance with ACI 318 by field strength tests, strength test records or trial mixtures.
E. Concrete Mix Designs: submit mix designs for each class of concrete.
1. Indicate the following for each mix design:
a. Class designation.
b. Proportions of cement, fine and coarse aggregates, and water.
c. Water-cement ratio, design strength, slump, and air content.
d. Type of cement and aggregates.
e. Type and dosage of admixtures.
2. Mix designs shall be adjusted as required by weather and jobsite conditions to maintain specified
strengths throughout the course of the work without additional cost to the Owner.
3. As strength data becomes available during the progress of the work, mix designs may be adjusted in
accordance with ACI 318.
4. Minimum Cement Content: Cement content shall not be less than 320 pounds per cubic yard.
5. Fly ash shall not be used in concrete mixtures exposed to view. Fly ash content shall be limited to 30
percent of weight of Type I Portland cement used.
F. Strength Gain: design concrete mixes to obtain required strengths in 28 days or less from date of placement.
2.09. PRODUCTION OF CONCRETE
A. Do not mix concrete for placement in the work until mix designs and corresponding strength tests reflect that
each proposed mix will develop strengths required and mix designs have been reviewed for compliance.
B. Batching and Mixing:
1. Batch and mix ready-mixed concrete in accordance with ASTM C94.
2. Batch site-mixed concrete with scales accurate to within 0.4 percent of their total capacities. Operation of
batching equipment shall consistently measure ingredients within 1 percent for concrete and water, 2
percent for aggregates and 3 percent for admixtures. Mixing of site-batched concrete shall be in
accordance ACI 301.
C. Admixtures: Air-entraining admixtures and other chemical admixtures shall be charged into mixer as solutions
and shall be accurately measured by means of a mechanical dispenser. The liquid shall be considered as part
of mixing water.
2.010. SOURCE QUALITY CONTROL
A. Laboratory Inspection
1. Verify required plant certifications
2. Inspect batching equipment periodically
3. Inspect batching and loading of transit-mix trucks at the start of each day of production.
B. Materials Testing
1. Sieve analysis of aggregates
PART 3 - EXECUTION
3.01. PREPARATION
A. Do not begin delivery of concrete materials until formwork, reinforcement, and all items required to be
embedded in the concrete are complete, properly positioned and secured in place.
1. Remove snow, ice, debris and excessive water from forms.
2. Pre-wet soil and sand subgrades and surfaces of precast concrete to receive fresh concrete.
3. Position and secure expansion joint materials, anchors, waterstops, screeds, control joint forms, and
expansion caps on slip-dowels.
4. Remove hardened concrete and foreign materials from the inner surfaces of conveying equipment,
formwork and reinforcing.
B. Prepare and have ready in good working condition chutes, tremies, pumps, buggies, vibrators and all other
equipment necessary for the orderly and continuous placement of concrete.
C. Place vapor barrier beneath all interior slabs. Inspect and repair vapor barrier prior to placing concrete.
3.02. INSTALLATION
A. Lack of Slope: Confirm with architect before proceeding when the Drawings show exterior flatwork without a
specific slope.
NAPA CENTURY CENTER XD 12
#165582