Question 1

Slump test

Accepted Answer

A measure of the consistency of fresh concrete, determined by inverting a standard cone filled with concrete and measuring the amount it subsides.

Question 2

Air-entrained concrete

Accepted Answer

Concrete containing microscopic air bubbles, typically added via an admixture, to improve freeze-thaw resistance and workability.

Question 3

Curing compound

Accepted Answer

A liquid applied to the surface of freshly placed concrete to reduce moisture loss, allowing for proper hydration and strength development.

Question 4

Bleed water

Accepted Answer

Excess water that rises to the surface of fresh concrete as it settles, which can cause surface defects if not properly managed.

Question 5

Delamination

Accepted Answer

The separation of the concrete surface layer from the underlying concrete due to improper finishing, excessive bleed water, or inadequate curing.

Question 6

Rebar

Accepted Answer

Steel reinforcement bars used to increase the tensile strength and ductility of concrete.

Question 7

Screed

Accepted Answer

A straightedge tool used to strike off and level fresh concrete to the desired elevation.

Question 8

Bull float

Accepted Answer

A large, flat tool used to smooth and level the surface of freshly placed concrete after screeding.

Question 9

Trowel

Accepted Answer

A handheld tool with a flat, smooth blade used for compacting, smoothing, and finishing the surface of concrete.

Question 10

Vibration

Accepted Answer

The process of mechanically consolidating fresh concrete to remove entrapped air and ensure proper contact with forms and reinforcement.

Question 11

Hydration

Accepted Answer

The chemical reaction between cement and water that causes concrete to harden and gain strength.

Question 12

Compressive strength

Accepted Answer

The maximum load a concrete sample can withstand before failure when subjected to compression.

Question 13

Flexural strength

Accepted Answer

The ability of concrete to resist bending or flexing forces, measured as the modulus of rupture.

Question 14

Water-cement ratio

Accepted Answer

The ratio of the weight of water to the weight of cement in a concrete mix, which influences strength, durability, and workability.

Question 15

Aggregate

Accepted Answer

The granular materials, such as sand, gravel, or crushed stone, used in concrete to provide bulk and strength.

Question 16

Fineness modulus

Accepted Answer

An index that represents the average size of the particles in a given aggregate, used to determine the proportions in a concrete mix.

Question 17

Admixture

Accepted Answer

A material added to the concrete mix, other than cement, water, and aggregate, to modify its properties.

Question 18

Concrete mix design

Accepted Answer

The process of selecting the appropriate proportions of cement, water, aggregate, and admixtures to achieve desired concrete properties.

Question 19

Consolidation

Accepted Answer

The process of eliminating entrapped air and voids in freshly placed concrete to ensure proper contact with forms and reinforcement.

Question 20

Cold joint

Accepted Answer

A discontinuity in concrete resulting from the hardening of one layer before the next is placed, which can lead to a weakened bond.

Question 21

Accelerator

Accepted Answer

An admixture that speeds up the rate of hydration and setting of concrete, allowing it to gain strength more quickly.

Question 22

Retarder

Accepted Answer

An admixture that slows down the rate of hydration and setting of concrete, providing more time for placement and finishing.

Question 23

Efflorescence

Accepted Answer

A white, powdery deposit of salts on the surface of concrete caused by the migration of soluble salts to the surface as moisture evaporates.

Question 24

Plastic shrinkage

Accepted Answer

The reduction in volume of fresh concrete due to the loss of water, which can cause cracking if not properly controlled.

Question 25

Autogenous shrinkage

Accepted Answer

Volume reduction in concrete caused by self-desiccation, or the consumption of water in the hydration process.

Question 26

Drying shrinkage

Accepted Answer

The reduction in volume of hardened concrete due to the loss of moisture, which can cause cracking and curling.

Question 27

Control joint

Accepted Answer

A planned joint in a concrete slab that allows for movement and helps to prevent random cracking.

Question 28

Expansion joint

Accepted Answer

A separation between adjoining concrete sections that allows for expansion and contraction due to temperature changes, preventing cracking.

Question 29

Isolation joint

Accepted Answer

A joint that separates a concrete slab from other elements or structures, allowing for independent movement and minimizing stress transfer.

Question 30

Dowel

Accepted Answer

A short, cylindrical steel bar used to provide load transfer between adjacent concrete slabs or sections while allowing for horizontal movement.

Question 31

Bond breaker

Accepted Answer

A material applied between fresh concrete and an existing surface to prevent adhesion and allow for movement.

Question 32

Honeycombing

Accepted Answer

Void areas in concrete caused by inadequate consolidation or the segregation of aggregate, which can reduce strength and durability.

Question 33

Spalling

Accepted Answer

The breaking away or chipping of the concrete surface, often caused by freeze-thaw cycles, corrosion of reinforcement, or impact damage.

Question 34

Scaling

Accepted Answer

The flaking or peeling of the concrete surface due to freeze-thaw cycles, deicing chemicals, or improper finishing and curing.

Question 35

Creep

Accepted Answer

The gradual, time-dependent deformation of concrete under sustained load, which can cause deflection or cracking.

Question 36

Carbonation

Accepted Answer

The reaction between carbon dioxide in the atmosphere and the calcium hydroxide in concrete, which can lead to the corrosion of reinforcement.

Question 37

Alkali-silica reaction (ASR)

Accepted Answer

A chemical reaction between the alkalis in cement and reactive silica in certain aggregates, causing expansion and cracking in concrete.

Question 38

Shotcrete

Accepted Answer

A method of placing concrete by projecting it at high velocity onto a surface, often used for repair work or irregularly shaped structures.

Question 39

Self-consolidating concrete (SCC)

Accepted Answer

A highly flowable concrete mix that can be placed without the need for vibration, providing improved consolidation and surface finish.

Question 40

Pre-stressed concrete

Accepted Answer

Concrete in which internal stresses are introduced to counteract external loads, often by tensioning steel reinforcement before the concrete hardens.

Question 41

Post-tensioned concrete

Accepted Answer

A type of pre-stressed concrete in which steel tendons are tensioned after the concrete has hardened, applying compressive stress to the concrete.

Question 42

Flatness (FF) and Levelness (FL)

Accepted Answer

Two numerical indices used to evaluate the flatness (FF) and levelness (FL) of a concrete floor, based on the deviation from an ideal plane.

Question 43

Power float

Accepted Answer

A machine with rotating blades used to smooth and finish large areas of concrete, providing a high-quality, dense surface.

Question 44

Vapor barrier

Accepted Answer

A layer of material placed beneath a concrete slab to prevent moisture migration from the ground, which can cause flooring issues or reduced durability.

Question 45

Superplasticizer

Accepted Answer

A high-range water-reducing admixture that increases the workability of concrete, allowing for easier placement and reduced water content without affecting strength.

Red Seal Exam Concrete Finisher: Advanced Flash Cards