Rapid Strength Concrete (RSC) RAPID S TRENGTH CONCRETE (RSC)
Part 1 — General
1.1 Section Includes
A.Rapid Strength Concrete (RSC)
1.2 Related Sections
A.Sectio n 03055: Portland Cement Concrete
1.3 References
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.ASTM C 157: Length Change of Hardened Hydr aulic-Cement Mortar and Concrete
F.ASTM C 309: Liquid Membrane- Forming Compounds for Curing Concrete
G.ASTM C 1074: Estimating Concrete Strength by the Maturity Method
H.ASTM C 1600: Rapid Hardening Hydraulic Cement
I.ASTM C 1602: Mixing Water Used in the Production of Hydraulic Cement Concrete
J.UDOT Materials Manual of Instruction
K.UDOT Minimum Sampling and Testing Requirements Rapid Strength Concrete (RSC)
1.4 Definitions
A.Cold Weather Protection Period – The required time during which the concrete is maintained at or above a specific temperature to prevent freezing of the concrete and to provide the necessary strength development for structural safety.
B.Production Day – A 24 hour period in which RSC is being placed
1.5 Submittals
A.Mix Design to be used for approval
1.The Department approves concrete mix designs based on trial batch test results.
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 Section 03055, Article 2.2, paragraph B.
d.Written plan for admixtures
3.Submit a new mix design for approval, whenever the source of any mix component change s.
4.Mix designs are valid for one year from date of approval.
B.Cold Weather Concreting Plan and Hot Weather Concreting Plan for review.
1.Include the following:
a.Detailed procedures for monitoring and maintaining temperatures of all mix components including water, aggregates, and all other admixtures .
b.Detailed procedures for the mixing, placement, protection, curing, and temperature monitoring of concrete
c.Procedures to be implemented upon abrupt changes in weather conditions or equipment failures.
d.Refer to this Section, Article 3.3, paragraph D for cold weather concreting requirements and Article 3.3, paragraph E for hot weather concreting requirements.
C.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 Rapid Strength Concrete (RSC)
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
1.6 Acceptance
A.General acceptance will be based on a comparison of the approved 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 T able 1 and adjust mix proportions as necessary
B.Acceptance sampling and testing of material is according to UDOT Minimum Sampling and Testing Requirements
C.The Department rejects the portion of a lot represented by a strength test that is more than 500 psi below the 28 Day Minimum Compressive Strength f ’c (psi) in Table 1.
1.The Engineer may accept reject material based on the materials dispute resolution process.
a.The Department applies a 0.50 pay factor to the pay item for the quantity represented if reject material is allowed to remain in -place.
2.The Department will monitor the strength test results and may un- approve the mix design based on low strength test results.
D.The Department will obtain one 8 oz cement powder sample per production day from the volumetric mix er at the job site. Rapid Strength Concrete (RSC)
Part 2 — Products
2.1 Concrete Mix Requirements
A.Use only concrete mixes that have a Department approved mix design.
1.Refer to the requirements in Table 1. Table 1 Property Test method Requirements Air Entrainment AASHTO M 154 including Section 5 5.0% - 7.5% 3 Day Flexural Strength AASHTO T 97 550 psi minimum 28 Day Flexural Strength AASHTO T 97 650 psi minimum 4 hour Compressive strength AASHTO T 22 4000 psi minimum Mix Design Compressive Strength f ’cr (psi) AASHTO T 22 5200 psi minimum 28 Day Compressive Strength f ’c (psi) AASHTO T 22 4000 minimum 4 hour Drying shrinkage ASTM C 157 0.04 maximum 28 Day Drying shrinkage ASTM C 157 0.04 maximum Water/Cement Ratio by weight 0.38 - 0.44
2.2 Materials
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 m eets ASTM C 1602, including Table 2.
D.Admixtures
1.Meet the requirement s of Section 03055, Article 2.2, paragraph D .
E.Curing Compound
1.Refer to ASTM C 309, Type 2, Class B. Rapid Strength Concrete (RSC)
2.3 Mix Design
A.Design mixes to meet the requirements of this Section and project specific criteria.
B.The Contractor assumes responsibility for the compatibility of admixtures with the mix design and their potential effects on concrete properties.
C.Obtain approval from the Engineer for the project specific application of an approved mix design.
2.4 Trial 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 h our, 7 d ay and 28 d ay shrinkage tests – Refer to ASTM C 157
C.Use the same components in the trial batches to be used in pro duction.
D.Use Department Certified TTQP Concrete and Concrete Strength Testing personnel to perform trial batches and strength tests.
E.The Department or its representative may witness the trial batch.
F.Use a Department qualified laboratory to verify trial batch compressive and flexural strength testing.
G.Mix concrete trial batches using the volumetric mix er 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.
2.5 Equi Pment
A.Volumetric Mixer Truck
1.The volumetric mixer truck i s required to have a current UDOT certification and calibrated annually. Rapid Strength Concrete (RSC)
B.Maturity Meters
1.Produce computer generated printout of the data logger.
2.Provide sensor probes .
Part 3 — Execution
3.1 Concrete Mixing
A.Volumetric truck mixing
1.Aggregates must be dried and drained to a stable moisture content prior to loading .
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.
7.Do not apply finishing aids to the concrete surface.
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 c ontain and properly dispose of any wash water and associated concrete residue.
3.2 Curing
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 ft 2/gal.
2.Prevent damage to the pavement surface texture.
B.Follow any additional cement manufacturer curing requirements. Rapid Strength Concrete (RSC)
C.Refer to Section 03055 for cylinder storage requir ements.
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.
3.3 Pre-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.
2.Concrete protection.
3.Washout bin staging.
4.Handling of concrete cylinders.
5.Placement of maturity meters.
6.Opening to traffic.
3.4 Limitations
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 te mperature is between 50 and 80 degrees F , taken immediately after discharge of chute, unless otherwise specified.
C.Cold Weather – Comply with the following when the ambient temperature is forecast to drop below 40 degrees F before the concrete reaches a compressive strength of 3500 psi as determined by the maturity method.
1.Follow the authorized cold weather plan.
2.Provide necessary cold weather protection for mixing, placing, finishing, curing, and protecting in- place concrete.
3.Blank et concrete immediately after curing compound is applied.
4.Do not use chemical anti -freeze additives in the concrete.
5.Maintain the temperature of the concrete above 50 degrees F during mixing, plac ing, and curing.
6.Do not proceed with placement of concrete if the temperature of all contact surfaces, including reinforcement, is less than 36 degrees F. Rapid Strength Concrete (RSC)
D.Hot Weather – Comply with the following when mixing, placing, finishing, curing, and protecting concrete exposed to hot weather until the concrete reaches a compressive strength of 30 00 psi as determined by the maturity method.
1.Hot weather limitations apply at any time of the year when a combination of high ambient temperature, high concrete temperature, low relative humidity, and high wind speed have the potential to impair the quality of the concrete by accelerating the rate of moi sture loss and rate of cement hydration, or otherwise causes detrimental results.
2.Follow the authorized hot weather plan.
3.Do not proceed with the placement when the temperatures of all contact surfaces, including reinforcement, are greater than 95 degrees F.
4.Cool all surfaces that will come in contact with the concrete to below 95 degrees F.
Source: Utah Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 904–911 of 1,331.