click below
click below
Normal Size Small Size show me how
Concrete Materials
Concrete Materials Final Spring 2012
Question | Answer |
---|---|
Low temperature curing results in high early strength but lower ultimate | False |
The main hydration compound responsible for strength of Portland cement concrete is ettringite | False |
The use of air-entraining admixture would typically allow the reduction of the w/c ratio required for a given work ability | True |
Effectiveness of a mineral admixture as a pozzolanic material can be assessed through quantifying lime consumption of that admixture when incorporated with cement in a mix | True |
Increasing the fineness modulus of sand increases paste requirement | |
Increasing maximum aggregate size results in a decrease in the compressive strength of concrete in lean mixes while for mix mixtures the opposite is true | False |
OD AND SSD are considered reference moisture states for aggregates | True |
In order to increase sulfate durability of a structure, a portland cement of high tricalcium aluminate content should be selected. | False |
The main contributiion to heat evolution during the hydration of Portland cement is primarily from C2S hydration | False |
In Preparing a trial batch for a specific concrete mix, it is important to batch by mass as opposed to batching by volume | True |
The initial set of a cement paste can be correlated to the end of induction stage of tricalcium sillicate hydration | |
For mass elements or mass structures it is important to use Portland cement that is high in its tricalcium aluminate and tricalcium silicate content | False |
In order to improve durability of reinforced structures, it is important to incorporate a mineral admixture such as silica fume or fly ash | True |
The primary focus of civil engineers in designing a structural element is to aim for the highest compressive strength without accounting for durability | False |
For mass concrete, cement fineness has no consequences on structure durability | False |
The heat of hydration of Portland Cement paste will not be affected by a large increase in cement fineness | False |
For the same workability, a low w/c ratio design will yield concrete that is strong a durable | True |
Reducing the transition zone in concrete has no effect on concrete strength | False |
The pH of the pore solution is affected by the alkali content of Portland cement | |
It is important to limit periclase in portland cement because it can generate unsoundness in concrete elements | True |
The amount of sulfur trioxide in portland cement is not of significance on a sulfate durability | False |
On hydration anyhydrous portland cement doubles its volume | True |
The moisture content of aggregates has to be accounted for to ensure a constant w/c ratio in making concrete trial batches | True |
Bogue calculations give an accurate account of the crystalline phases in portland cements | False |
For lean mixes, increasing nominal maximum aggregate size increases the compressive strength of the concrete | True |