Final Flashcards
Rate of loading for running a Compressive strength test is
20-50 psi/second
Rate of loading for running Splitting tensile test is
100-200 psi/minute
Rate of loading for running Rupture tensile test (beam test) test is
125-175 psi/ minute
If a water reducer is added to the concrete mix without changing other ingredients, what will happen to the properties of the concrete?
It will increase the slump or Workability
If a water reducer is added to the concrete mix without changing other ingredients, and the intention of adding the water reducer is to increase the compressive strength of
hardened concrete, how this can be achieved?
Reduce w/c, and keeping the same slump
In making a slump test, the cone should be filled in
3 layers
In making a slump test, each layer should be equal
4 inches
In making a slump test, each layer should be rodded
25 times per layer
Concrete should have the desired ______________ before beginning any other tests.
Slump
A load of 200,000 pounds was recorded from testing a 6 in. x 12 in. concrete cylinder under
compression. The concrete compressive strength is ________psi.
7077.15
f ′c=P/A
Where:
f′c is the compressive strength, P is the load applied, and A is the cross -sectional area.
Given:
P = 200,000lbs
A is a cylinder so area is pi*radius(r)^2
Solve:
Given that the diameter of the cylinder is 6 inches, the radius (r) is (6/2) = 3 inches.
A = pi3^2 = pi9 = 28.27in^2
so
f’c = 200,000/28.27 = 7077.15 psi
The splitting tensile strength of a 6 x 12 in. concrete cylinder is ____ psi for a recorded failure
load of 56520 pounds.
500
The modulus of rupture of a standard beam test specimen (ASTM C78) (6 x 6 x 18 in.) is _____ psi for a recorded failure load of P = 6000 pounds
500
Define High Performance Concrete and how do we achieve HPC Mix?
High-Performance Concrete (HPC) is concrete that meets specific performance and composition requirements. Achieving an HPC mix involves using high-strength materials, careful proportioning, and often incorporating supplementary cementitious materials.
Describe elastic and inelastic deformation?
Elastic deformation refers to reversible, temporary changes in shape under load, like stretching a rubber band. Inelastic deformation, on the other hand, is permanent and occurs when the material undergoes plastic deformation or fractures.
Define toughness of fibrous concrete beams?
The ability to resist damage by holding the broken cement together via fibrous strands
Define pervious concrete and what are the advantages of using this concrete?
Pervious concrete is actually designed to be more porous, allowing water to pass through. It’s often used for stormwater management. The correct definition is: Pervious concrete is a special type of concrete with high porosity that allows water to pass through it, promoting water infiltration and reducing runoff. The advantages include improved stormwater management, reduced flooding, and groundwater recharge.
The property that reflects the ease or difficulty in placing and finishing freshly mixed
concrete, is called:
Workability
The bonding agent used in a concrete mix is:
Cement
A material used for the purpose of delaying the setting time of concrete is:
Retarding admixture
The weight of one gallon of water is:
8.33lbs
The ability of hardened concrete to resist the deterioration caused by weathering, chemicals,
and abrasions is known as:
Durability
The IDOT allowable range for air content in concrete pavement and bridge decks is:
5.0 - 8.0
The most important effect of entrained air in concrete is to:
Increase durability
Air entrainment admixture must be dispersed into the concrete mixer with:
Water
