ASTM C138 TESTS WITH ANSWERS A+ GRADE.
The gravimetric air content of a mixture is computed using the following equation, where T is the
theoretical density and D is the measured density of a mixture - A = [T - D] / T x 100
After consolidating a layer by vibration, tap the outside of the Measure 10 to 15 times with the mallet -
False
*mallet is used only when rodding*
The density of a concrete mixture is computed to be 142. 568 lb/ft3. The density should be reported as -
142.6 lb/ft^3
Report the yield of a concrete mixture to the nearest - 0.1 yd^3
The volume of a measure is 0.510 ft^3. The net mass of concrete in the measure is 72.3 lb. Calculate the
density of the concrete. - (72.3 lb) / (0.510 ft^3) = 141.8 lb/ft^3
*equation : D = (net mass of measure) / (volume of measure)*
The total mass of all materials in a batch of concrete is 26,520 lb. The measured density for the mixture is
144.3 lb/ft^3. Calculate the yield in cubic yards for the batch - (26,520 lb) / (144.3 x 27) = 6.8 yd3
*equation : Y = M / (D x 27)*
the design yield for a batch is 8.5 yd^3. The actual yield for the batch is 8.7 yd^3. Calculate the relative
yield. - (8.7) / (8.5) = 1.02
*equation : R = calculated yield / design yield*
The theoretical density of a mixture is 151.2 lb/ft^3. The measured density for the mixture is 142.6
lb/ft^3. Calculate the gravimetric air content for the mixture - [(151.2 - 142.6) / 151.2] x 100 = 5.7%
*equation : A = [(T - D) / T] x 100 *
When rodding each upper layer of concrete, allow the rod to penetrate through the layer ring rodded and
into the layer below approximately - 1 inch
The gravimetric air content of a mixture is computed using the following equation, where T is the
theoretical density and D is the measured density of a mixture - A = [T - D] / T x 100
After consolidating a layer by vibration, tap the outside of the Measure 10 to 15 times with the mallet -
False
*mallet is used only when rodding*
The density of a concrete mixture is computed to be 142. 568 lb/ft3. The density should be reported as -
142.6 lb/ft^3
Report the yield of a concrete mixture to the nearest - 0.1 yd^3
The volume of a measure is 0.510 ft^3. The net mass of concrete in the measure is 72.3 lb. Calculate the
density of the concrete. - (72.3 lb) / (0.510 ft^3) = 141.8 lb/ft^3
*equation : D = (net mass of measure) / (volume of measure)*
The total mass of all materials in a batch of concrete is 26,520 lb. The measured density for the mixture is
144.3 lb/ft^3. Calculate the yield in cubic yards for the batch - (26,520 lb) / (144.3 x 27) = 6.8 yd3
*equation : Y = M / (D x 27)*
the design yield for a batch is 8.5 yd^3. The actual yield for the batch is 8.7 yd^3. Calculate the relative
yield. - (8.7) / (8.5) = 1.02
*equation : R = calculated yield / design yield*
The theoretical density of a mixture is 151.2 lb/ft^3. The measured density for the mixture is 142.6
lb/ft^3. Calculate the gravimetric air content for the mixture - [(151.2 - 142.6) / 151.2] x 100 = 5.7%
*equation : A = [(T - D) / T] x 100 *
When rodding each upper layer of concrete, allow the rod to penetrate through the layer ring rodded and
into the layer below approximately - 1 inch
