LCI Preconstruction & Estimating Training Manual

11/22/2017

Properties of Concrete

On Site Concrete Testing (2)

- Strength - Permeability - Shrinkage -Creep

• Concrete strength unclear after pour • Take cores of the columns and slabs • Cast in Place Punch Out Cylinder

Properties of Cement Matrix

Concrete Testing

On Site Concrete Testing (3)

• Stronger in compression than in tension • Cylindrical concrete crushed • Tests conducted after 7, 14, 28 and 51 days • Pressure calculated in pounds per square inch

• Maturity Meters • Winter conditions concrete does not cure as quickly • Confirm concrete strength prior to pulling formwork

Types of Concrete

Pricing in cubic yard (CY) or square feet (SF)

On Site Concrete Testing (1)

Regular Strength

High Strength

Low Strength

Between 1480 psi and 6000 psi

Greater than 6000 psi

Less than 1480 psi

• Strength of concrete on site using a rebound hammer: ▫ Schmidt hammer ▫ Swiss hammer • Hammer measures the rebound of a spring loaded mass impact • Determine compressive strength

Purpose: - Structural Beams and Columns - Foundations -Bridge piers - Roads and Highways

Purpose: - Rarely used in construction - Floor slabs -Flow-able Fill - Back fill

Purpose:

- High Early -Dams - Marine Foundations - Parking Garages

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