RAPID STRENGTH CONCRETE (RSC)
PART 1 GENERAL
1.1SECTION INCLUDES
A.Rapid Strength Concrete (RSC)
1.2RELATED SECTIONS
A.Section 03055: Portland Cement Concrete
1.3REFERENCES
A.AASHTO M 154: Air-Entraining Admixtures for Concrete
B.AASHTO M 157: Ready-Mixed Concrete
C.AASHTO T 22: Compressive Strength of Cylindrical Concrete Specimens
D.AASHTO T 97: Flexural Strength of Concrete (Using Simple Beam with
Third-Point Loading)
E.ACI 301: Specification for Structural Concrete
F.ASTM C 157: Length Change of Hardened Hydraulic-Cement Mortar and
Concrete
G.ASTM C 309: Liquid Membrane-Forming Compounds for Curing Concrete
H.ASTM C 1074: Estimating Concrete Strength by the Maturity Method
I.ASTM C 1600: Rapid Hardening Hydraulic Cement
J.ASTM C 1602: Mixing Water Used in the Production of Hydraulic Cement
Concrete
K.UDOT Materials Manual of Instruction
Rapid Strength Concrete (RSC)
1.4DEFINITIONS
A.Production Day – A 24 hour period in which RSC is being placed
1.5SUBMITTALS
A.Mix Design to be used for review
1.The Department may authorize concrete mix designs based on trial
batch test results or on Department project history.
a.Strength test results will be evaluated using f ’c criteria of
ACI 301.
b.Acceptable history will include a review of all test results on
UDOT projects within the past 12 months and must include a minimum of 15 tests.
2.Include at least the following:
a.The proposed mix design using the same format and units
used by the volumetric mixer printout.
b.Trial batch test results.
c.Test results verifying that coarse and fine aggregates meet
d.Written plan for admixtures. Refer to Section 03055.
B.Cold Weather Concreting Plan for review. Refer to Section 03055.
C.Evaporation Monitoring and Control Plan, for review. Refer to Section
03055.
D.Volumetric mixer daily production data in electronic or printed media at the
end of each production day, including the following:
1.Weight of cement per revolution count
2.Weight of each aggregate size per revolution count
3.Gate openings for each aggregate size.
4.Weight of water added to the concrete per revolution count
5.Moisture content of each aggregate size
6.Individual volume of admixtures per revolution count
7.Time of Day
8.Day of week
9.Production start and stop times
10.Volumetric mixer identification
11.Specific mix design of concrete being produced
12.Source of the individual aggregate sizes
13.Source, brand, and type of cement
14.Source, brand, and type of individual admixtures
15.Name and signature of the operator
Rapid Strength Concrete (RSC)
E.Construction Documentation
1.Concrete surface temperature monitoring for information. Refer to
Section 03055.
2.Site Evaporation Monitoring data for information. Refer to Section
03055.
1.6ACCEPTANCE
A.General acceptance will be based on a comparison of the mix design and
the printed ticket.
1.Verify correct amount of air entraining admixture is added and
adjust mix proportions as necessary
2.Verify water/cement ratio meets the requirements of Table 1 and
adjust mix proportions as necessary
B.The Department rejects the portion of a lot represented by a strength test
that is more than 500 psi below the 28 Day Compressive Strength f ’c (psi) in Table 1.
1.The Engineer may accept reject material based on an engineering
analysis that demonstrates that the compressive strength is adequate to serve the design purpose.
a.The Department applies a 0.50 pay factor to the quantity
represented if reject material is allowed to remain in-place.
2.The Department will monitor the strength test results and may un-
authorize the mix design based on low strength test results.
C.The Department will obtain one 8 oz cement powder sample per
production day from the volumetric mixer at the job site.
PART 2 PRODUCTS
2.1CONCRETE MIX REQUIREMENTS
A.Use only concrete mixes that have a Department authorized mix design.
1.Refer to the requirements in Table 1.
Rapid Strength Concrete (RSC)
Table 1 Property Test method Requirements AASHTO M 154 Air Entrainment including Section 5 5.0%- 7.5% 3 Day Minimum Flexural Strength (psi) AASHTO T 97 550 28 Day Minimum Flexural Strength (psi) AASHTO T 97 650 4 hour Minimum Compressive strength (psi) AASHTO T 22 4000
28 Day Minimum Compressive Strength f ’c (psi) AASHTO T 22 4000 4 hour Maximum Drying shrinkage ASTM C 157 0.04 28 Day Maximum Drying shrinkage ASTM C 157 0.04 Water/Cement Ratio by weight 0.38 - 0.44
2.2MATERIALS
A.Cement
1.Use RSC meeting the requirements of ASTM C1600.
2.Do not use pozzolans.
B.Aggregate
1.Meet the requirements of Section 03055, Article 2.2, paragraph B
a.Use a 3/4 inch coarse aggregate gradation or no course
aggregate.
C.Water
1.Use potable water or water that meets ASTM C 1602, including
Table 2.
D.Admixtures
1.Meet the requirements of Section 03055, Article 2.2, paragraph D.
E.Curing Compound
1.Refer to ASTM C 309, Type 2, Class B.
2.3MIX DESIGN
A.Design mixes to meet the requirements of this Section and project specific
criteria.
Rapid Strength Concrete (RSC)
B.The Contractor assumes responsibility for the compatibility of admixtures
with the mix design and their potential effects on concrete properties.
2.4TRIAL BATCHES
A.Perform 1.5 hour, 2 hour, 2.5 hour, 3 hour, 3.5 hour, 4 hour, 6 hour, 24
hour and 28 day compressive strength tests – Refer to AASHTO T 22
1.Develop maturity meter curves, Nurse-Saul method, for use in
opening to traffic – Refer to ASTM C 1074.
B.Perform 4 hour, 24 hour, 7 day and 28 day shrinkage tests – Refer to
ASTM C 157
C.Use the same components in the trial batches to be used in production.
D.Use Department Certified TTQP Concrete and Concrete Strength Testing
personnel to perform trial batches and strength tests.
E.Use a Department qualified laboratory to verify trial batch compressive
and flexural strength testing.
F.Mix concrete trial batches using the volumetric mixer truck to be used in
production if a volumetric truck is used in production; otherwise, mix concrete trial batches according to the UDOT Materials Manual of Instruction 974; Guidelines for Portland Cement Concrete Mix Design Trial Batches.
2.5EQUIPMENT
A.Volumetric Mixer Truck
1.The volumetric mixer truck is required to have a current UDOT
certification and calibrated annually.
B.Maturity Meters
1.Produce computer generated printout of the data logger.
2.Provide sensor probes.
PART 3 EXECUTION
3.1GENERAL
A.Volumetric truck mixing
1.Aggregates must be dried and drained to a stable moisture content
prior to loading. Rapid Strength Concrete (RSC)
2.Free moisture content of the fine aggregate must not exceed 8
percent of its saturated surface-dry weight.
3.Do not use ice to cool directly. Ice must be melted before entering
the mixer if ice is used to cool the mix water.
4.Proportion and charge the cement into the volumetric mixer such
that there is no variance of the required quantity due to conditions such as wind or accumulation of equipment.
5.Do not mix more material in the volumetric mixer than will allow
complete mixing.
6.Do not add water after discharge.
B.Batch plant mixing
1.Batch Tolerances. Refer to AASHTO M 157.
a.Cementitious Material: ± 1 percent of the required mass.
b.Aggregate: ± 2 percent of the required mass.
c.Total Water: ± 3 percent of the required mix amount.
2.Limit loads to 6.5 cu yd.
C.Truck Washout
1.Provide, at jobsite, a washout bin of sufficient size to contain and
properly dispose of any wash water and associated concrete residue.
D.Do not apply finishing aids to the concrete surface.
3.2CURING
A.Apply concrete curing compound to the entire concrete surface
immediately after surface finishing of individual placements.
1.Apply at an approximate application rate of 200 ft2/gal.
2.Prevent damage to the pavement surface texture.
B.Follow any additional cement manufacturer curing requirements.
C.Refer to Section 03055 for cylinder storage requirements.
1.Do not move concrete test cylinders from placement area for at
least 4 hours.
2.Remove concrete test cylinders from job site immediately before
opening for traffic or at 4 hours, whichever is later.
3.3PRE-ACTIVITY MEETING
A.Conduct pre-activity meeting with Department representative, contractor,
and RSC supplier before any concrete placement and discuss the following:
1.Concrete curing.
Rapid Strength Concrete (RSC)
2.Concrete protection.
3.Washout bin staging.
4.Handling of concrete cylinders.
5.Placement of maturity meters.
6.Opening to traffic.
3.4LIMITATIONS
A.Do not open to traffic until material reaches a compressive strength of
3000 psi based on maturity meter.
1.Place the maturity meter in the last placement of the production day.
2.Concrete compressive strength of 3500 psi is required in cold
weather.
B.Concrete Temperature – Place concrete when the concrete temperature is
between 50 and 80 degrees F, taken immediately after discharge of chute, unless otherwise specified.
C.Cold Weather Concreting – Refer to Section 03055.
D.Evaporation Monitoring and Control – Refer to Section 03055.
END OF SECTION
Rapid Strength Concrete (RSC)
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Source: Utah Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 904–911 of 1,331.
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