Concrete Strength Tests: Compressive and Flexural Strength

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Which ASTM standard is the most common test for measuring the compressive strength of concrete?

ASTM C93
ASTM C39 (correct)
ASTM C78
ASTM C6

What is the minimum required cross-section for the flexural strength test of concrete as per ASTM C78?

6x6 inches (correct)
8x8 inches
10x10 inches
4x4 inches

What is the purpose of conducting compressive and flexural strength tests on concrete?

To evaluate the durability of the concrete
To determine the workability of the concrete mix
To measure the tensile strength of the concrete
To validate the proper construction procedures on-site (correct)

What is the most common reinforcing material used in reinforced concrete?

Steel bars (RSB) or welded wire mesh (C) Signup and view all the answers

What is the term used to describe concrete that is cast on-site, as opposed to precast concrete?

Cast-in-place concrete (D) Signup and view all the answers

What is the most likely course of action if a sample from an actual concrete pour fails to meet the desired strength requirements?

The structure will be subjected to strengthening, rehabilitation, or retrofitting (C) Signup and view all the answers

What is the primary purpose of a soil investigation before deciding on a foundation system?

To evaluate if the soil can hold the building mass (B) Signup and view all the answers

How many soil borings are typically conducted for a 2-storey building?

2-3 bore holes (D) Signup and view all the answers

What is the purpose of a Property Survey?

To establish the extent and geometry of the property boundaries (A) Signup and view all the answers

Which of the following is NOT a consideration when selecting a foundation system?

The size of the building lot (A) Signup and view all the answers

What is the primary purpose of an Existing Condition Survey?

To survey all utilities, infrastructure, and natural conditions above and below grade (B) Signup and view all the answers

What is the significance of conducting a proper soil investigation before deciding on a foundation system?

To ensure the soil can support the building mass and prevent potential issues (A) Signup and view all the answers

What is the purpose of a Round Gate Hopper?

To distribute concrete easily and accurately (D) Signup and view all the answers

How are Concrete Pump Booms typically mounted?

On booms for long-distance placements (A) Signup and view all the answers

What is the main function of the Mobile Pump's choke?

To control the flow of concrete (A) Signup and view all the answers

What is the purpose of a Mini-Hopper in a concrete structure?

To distribute concrete easily and accurately (C) Signup and view all the answers

How does a Mobile Conveyor Belt function in relation to concrete?

It moves concrete from one place to another (C) Signup and view all the answers

What distinguishes an Extended Gate Laydown Hopper from other types of hoppers?

It is designed for low loading height and site discharge (B) Signup and view all the answers

What is the primary purpose of supplying water to concrete surfaces during curing?

To keep the concrete continuously moist (B) Signup and view all the answers

Which of the following is NOT a recommended method for supplying water to concrete surfaces during curing?

Submerging the concrete surface in water (C) Signup and view all the answers

What is the purpose of control joints (also known as contraction joints) in concrete slabs?

To provide a weak spot where the slab can crack when thermal stresses exceed the strength of the concrete (B) Signup and view all the answers

Which of the following methods is NOT mentioned for forming control joints in concrete slabs?

Applying a chemical sealant to create a weak spot (C) Signup and view all the answers

What is the purpose of curing cast-in-place concrete?

To allow the concrete to achieve the desired properties for its intended use (C) Signup and view all the answers

What is a recommended method for placing concrete during hot weather?

Use concrete admixtures such as retardants to delay initial set (B) Signup and view all the answers

What is a typical requirement before pouring concrete?

Obtain a pouring permit from the structural engineer (D) Signup and view all the answers

Which method of consolidation is recommended for concrete members with a depth greater than or equal to 4 inches?

Mechanical concrete vibrator (A) Signup and view all the answers

When using a mechanical vibrator for consolidation, how far should it penetrate into the layer below?

6 inches (150 mm) (D) Signup and view all the answers

What is a recommended practice for construction joints?

Their locations must be specified and approved by the engineer (A) Signup and view all the answers

What is a recommended practice for cooling forms and subgrade before placing concrete in hot weather?

Cool forms with water and moisten subgrade to a dewy state (D) Signup and view all the answers