Examples: Tolls roads Public Streets Intersections Airport Other II. Specifications

1. Fast Track Concrete CIMT 210 Examples: Tolls roads Public Streets Intersections Airport Other II. Specifications Planning and Construction Materials Joint and Sealing Curing and Temperature Testing Opening Traffic III. Mix Design

2. Examples • Toll Roads • Tollway authorities lose revenue when lane are shut down and there is much congestion, forcing drivers to find alternate routes • Public Street • Residents can gain access to their driveway within 24 hours if they live on urban streets • Intersections • Intersection suffer more pavement distress because they connect 2 or more streets. Fast track allows intersections to completed before rush hour • Airports • Fast track concrete allows contractor to operate slipform equipment on the initial paving lanes sooner than normal.

3. Examples • Airports Initial paving lanes Interior lanes Paving interior lanes on an airport facility (note theuse of initial lanes for construction platform)

4. Specifications • Planning and Construction • Check access for local traffic • Evaluate Local Business Interuption • Check for any utility work. • Secure access for equipment and operation • Check pavement edge drop-off requirement • Check for crossovers that disrupt both directions of traffic • Evaluate detour routes for level of congestion and damage to road due to prolong construction activity • By specifying fast track concrete near the end of the day will facilitate startup for next day.

5. Specifications • Planning and Construction – no special equipment is required for construction • Well planned construction sequences are necessary for the accelerated process • Constructing test slabs will help inexperienced workers to work with the plastic properties of fast track concrete • Concrete haul distance should be considered • Agencies should not modify their smoothness specifications for fast track concrete pavements.

6. Specifications • Materials • There is no specific proportioning necessary for fast track concrete. • Refer to: ASTM C 150 Type I and III cements

7. Specifications • Materials • Cement – ASTM C 150 Type I and III cements • High levels of tricalcium silicates (C3S) and finely ground cement particles will generate strength quickly. • Type III cement, which is finer than other PC, • develops early strengths • The problems with Type III are false sets, and a demand for excessive water and air entraining • Type I and II require chemical admixtures to gain early strength.

8. Materials • Pozzolanic Materials – Fly Ash or Ground –Granulated Blast Furnace slag • These pozzalanic materials extend strength gained, because tricalcium silicates (C3S) • do not extend • Fly Ash Class C and F • Class C will lower water demand, improve workability and increase long term strength • Class F will not contribute to early strength, but will extend long term strength, reduce permeability, and will combat the effects of deleterious materials, sulfates or alkalis • Flyash can slow down hydration and the final set, due to the temperature drops in hydration. • (addition of admixtures is required) Specifications

9. Materials • Air- Entraining Admixtures –are used to entrain microscopic air bubbles • Entrained air improves concrete durability by • reducing the effects of Freeze/thaw behavior • Fast Track concrete needs the appropriate air content of 4.5% to 7.5%. • Higher percentages of entrained air can reduce the early and long-term strength, while lower percentages will reduce the concrete durability. Specifications

10. Specifications • Materials • Water – Reducing Admixtures reduce the water required for workability • These admixtures can also increase early strength by lowering the quantity of water necessary for hydration. • Water reducers lowers the number of cement particles agglomerations and disperse cement particles. • Type I is most effective in early strength with water reducers..

11. Specifications • Materials • Accelerating Admixtures –aids strength development and reduce initial set times by increasing the reaction rate of tricalcium silicates (C3S) • Accelerating admixtures generally consist of soluble inorganic salts or soluble organic compounds • Calcium Chloride (CaCl2) is the most common • accelerator, but is a corrosive to the reinforcing • steel.

12. Materials • Aggregates– Grading – There is a definite relationship between aggregate grading uniformity and concrete strength, workability and long –term durability • Workability –concrete with a well graded combined aggregate will often be much workable at a low slump than a poorly graded mixture having a higher slump. • Slump- measure consistency between batches, is affected by a difference of 3.5 inch when comparing a uniform grading over a similar gap graded mix. The amount of water in the mix controls. (20-30 lbs difference) • Particle Shape and Texture – Sharp • particles are less workable than rounded • particles, but add to strength. Specifications

13. Materials • Water – Hydration is an exothermic process • Raising the Heat of Water can accelerate the process of hydration. (i.e. small projects, and intersections reconstruction) • Hot water is a catalyst for early hydration but it only good for short term. Several hours of heat containment require insulation for rapid strength gain. Specifications

14. Specifications • Joint and Sealing • Sawing – the time for sawing (sawing window) is reduced with Fast Track concrete. • Light saws which handle easy and are more versatile are more effective in Fast Track Concrete • Curing blanket is normally in place during the sawing operation and have to be removed

15. Specifications • Joint and Sealing • Mixes with softer limestone aggregate require less strength for sawing than do mixes with harder coarse aggregate • Contractors have successfully cut joints in fast-track construction using wet-sawing, dry-sawing and ultra – light sawing • Dry saw cutting can be performed earlier than wet-saw cutting

16. Specifications • Joint and Sealing • Liquid sealant - Cleaning is the most important aspect of joint • Reservoir faces require a thorough cleaning to be sure of good sealant adhesion • Proper cleaning after wet sawing requires mechanical action and pure water flushing to remove contaminants • Dry Sawing requires only an air blowing operation to remove particulate residue from the joint reservoir. (excessive dust is produced) • Preformed seals are not sensitive to dirt or moisture on side walls and may allow sealing earlier than any liquid seal.

17. Specifications • Curing and Temperature Maintenance – is important for the hydration within the concrete and also to prevent thermal cracking. • Monitoring of heat is required, so that contractors can adjust curing measures • Maturity testing allows for the field measurements of the concrete temperature to correlate with the gained strength • (see non-destructive testing) • Curing Compounds are liquid – membranes meeting ASTM C309. The materials create a seal that limits evaporation of mix water. The white color also reflects solar radiation • Class A liquid curing compounds are sufficient for fast track concrete

18. Specifications • Curing and Temperature Maintenance – (Continued) • Blanket Insulation – provide a uniform temperature environment for the concrete.It keeps the area dampened and reduce heat loss. Contractor will usually place blankets soon after applying curing compound • It is recommended that blankets should be applied after joint sawing is completed • Sawing Window – The sawing window is a short period after placement when the concrete can be cut successfully before it cracks. • The window ends when significant concrete shrinkage occurs and induces uncontrolled cracking.

19. Specifications • Curing and Temperature Maintenance – (Continued) • Plastic Shrinkage – forms after concrete placement due to rapid evaporation of water at the surface of the slab. • Ways to prevent evaporation conditions: • To pave during the evening or nighttime • To water mist aggregate stockpiles and subbase • To use evaporative retardant • When evaporation rate exceeds 0.2 #s/sft/hr then plastic shrinkage cracking is likely to occur.

20. Specifications • Testing – Non- Destructive • Maturity Testing – provides strength evaluation through monitoring of internal concrete temperature in the field. • The Nurse-Saul Method – calculates the time-temperature factor

21. Specifications • Testing – Non- Destructive (Maturity Test) • Arrhenius Maturity Equation – • See ASTM C 1074 • Field maturity begins with embedment of thermocouples or temperature probes and then compared to the laboratory study.

22. Specifications • Testing – Non- Destructive (Pulse Velocity) • Pulse-Velocity – measured the time required for an ultrasonic wave to pass through concrete from one transducer to another. • The velocity of the wave correlates to concrete strength or stiffness.

23. Specifications • Opening Traffic • Third –Point Flexural Strength (psi) – required to determine when roads should be open for traffic.

24. Specifications • Opening Traffic • The strength necessary to allow vehicles onto a new pavement will depend on the following factors: • Type, weight, and number of anticipated loads during early-age period • Location of loads on slab • Concrete Modulus of Elasticity • Pavement Design (new construction, unbonded overlay, bonded overlay, or overlay on asphalt) • Slab Thickness • Foundation Support (Modulus of Subgrade Reaction, K) • Edge support condition (widened lane or tied curb & gutter or tied concrete shoulder)

25. Specifications • Opening Traffic • Construction Traffic - typical construction vehicles include span saws, haul trucks and water trucks.

26. Specifications • Opening Traffic • Public Traffic - Flexural strength requirement for opening concrete pavements to use by public traffic. Traffic is an estimate of the total one-way ESAL’s that will use the pavement truck lane between time of opening and the time concrete reaches design strength (28 days)

27. Mix Design Various Mix Designs for Various Projects