prefi (t/f) Flashcards
experiments
The setting time of cement is influenced by factors such as the fineness of cement and the temperature of water.
True
The normal consistency of cement is expressed as a percentage of the weight of cement.
TRUE
The Los Angeles abrasion test is used to evaluate the hardness, strength, and durability of aggregates.
TRUE
The Los Angeles abrasion test results are expressed as a percentage of the original weight. This percentage is known as the Los Angeles Abrasion Value. The lower the value, the stronger the aggregate.
TRUE
The final setting time of cement is the time taken for the cement paste to reach its maximum strength and become fully hardened.
FALSE
The consistency of cement is influenced by factors such as the type of cement, water-cement ratio, temperature, and presence of admixtures.
TRUE
The strength of cement can be adversely affected by factors such as improper curing, excessive water content, and the presence of impurities.
true
The density of cement can vary depending on factors such as the type of cement and the fineness of the cement particles.
true
The specific gravity of cement is typically determined using the pycnometer method, where the cement sample is weighed in air and then weighed again when immersed in water.
TRUE
The absorption of coarse aggregates refers to the amount of water that can be absorbed by the aggregate particles, expressed as a percentage of the dry weight of the aggregate.
true
The absorption of fine aggregates can be determined by soaking the aggregates in water for a specified period of time and then weighing them to measure the increase in weight.
true
The absorption of fine aggregates refers to the amount of water that can be absorbed by the aggregate particles, expressed as a percentage of the dry weight of the aggregate.
TRUE
The absorption of fine aggregates can be determined by immersing the aggregates in water for a specified period of time and then weighing them to measure the increase in weight.
true
The moisture content of aggregates can affect the workability and strength of concrete mixtures.
true
The moisture content of aggregates is not affected by factors such as the weather conditions during transportation and storage.
FALSE
The slump of concrete is determined by measuring the vertical difference between the height of the mold and the height of the concrete after it settles.
true
The slump test can provide an indication of the water content and the overall quality of the concrete mixture.
true
During the curing process, it is important to prevent the concrete specimens from drying out too quickly, as rapid moisture loss can negatively impact their strength.
true
Curing compounds or plastic sheets can be used to cover the concrete specimens and retain moisture during the curing period.
TRUE
The curing period for concrete specimens can be extended beyond 7 days to achieve higher strength, depending on the specific requirements of the project.
TRUE
The normal consistency of cement refers to the water content required to produce a cement paste of standard consistency.
TRUE
The normal consistency of cement is determined by conducting the Vicat apparatus test with needle.
TRUE
The Los Angeles abrasion test is a method used to measure the degradation of mineral aggregates of standard gradings resulting from a combination of actions including abrasion or attrition, impact, and grinding in a rotating steel drum containing a specified number of steel spheres.
TRUE
In the Los Angeles abrasion test, the sample should be completely dry before testing.
TRUE
The setting time of cement refers to the time it takes for the cement paste to harden and gain strength.
TRUE
The initial setting time of cement is the time taken for the cement paste to lose its plasticity and become rigid..
TRUE
The strength of cement increases with age, as the hydration process continues, and the cementitious materials form stronger bonds.
TRUE
The density of cement is a measure of its mass per unit volume and is typically expressed in kilograms per cubic meter (kg/m3).
TRUE
The specific gravity of cement is the ratio of the density of cement to the density of kerosene at a specific temperature.
FALSE
The specific gravity of fine aggregates is a measure of their density compared to the density of water.
TRUE
The specific gravity of coarse aggregates can be determined using the water displacement method, where the aggregate is weighed in air and then weighed again when submerged in water.
TRUE
The specific gravity of fine aggregates is a measure of their mass compared to the mass of water.
FALSE
The specific gravity of coarse aggregates can be determined using the pycnometer method, where the aggregate is weighed in air and then weighed again when immersed in water.
TRUE
The moisture content of aggregates refers to the amount of water present in the aggregate particles, expressed as a percentage of the dry weight of the aggregates.
TRUE
The moisture content of aggregates can be determined by weighing a sample of the aggregates, drying it in an oven, and then re-weighing it to measure the loss in weight.
TRUE
The slump test is a commonly used method to measure the workability and consistency of fresh concrete.
TRUE
the slump test, a cone-shaped mold is filled with fresh concrete, and the mold is then lifted vertically, allowing the concrete to settle and spread.
TRUE
Concrete specimens are typically made by filling cylindrical molds with fresh concrete and compacting it using a mechanical tamper and tamping it 20 times per layer.
TRUE
The curing of concrete specimens involves providing optimal moisture and temperature conditions to facilitate the hydration process and achieve proper strength development.
TRUE
Concrete specimens should be cured in a controlled environment for a minimum period of 7 days to achieve adequate strength development.
TRUE
