Exam (elaborations)
CIM 3000 Written Exam 2 questions and answers verified 2024
- Course
- Institution
CIM 3000 Written Exam 2 questions and answers verified 2024
[Show more]
Content preview
CIM 3000 Written Exam 2Are aggregates classified according to density? - correct answer ✔Yes.
-Those used to make normal-density concrete are called normal-density
aggregated.
-Those for low-density concrete (historically known as "lightweight" concrete)
that have an air-dried density at 28 days usually in the range of 1440 to 1850
kg/m^3, are called low density aggregates.
-Those for high-density concrete, ranging in density from about 2880-5600
Kg/m^3, are called high-density aggregates.
What are the advantages of low-density aggregate? - correct answer ✔Low-
density aggregate is used to produce concrete with low density.
- Low-density aggregates provide thermal insulation, internal curing, and
better compatibility between the paste and the aggregate.
When is low density / nonstructural concretes used? - correct answer
✔Having an oven-dry density of 800 kg/m^3 or less. These concrete achieve
their low density by incorporating low-density aggregates, air entrainment, or
performed foam.
- These concretes are most commonly used in roof deck systems, where the
advantages include insulating value and improved fire resistance.
What are high-density aggregates? - correct answer ✔generally consist of
high-density minerals or rocks, or they consist of man-made materials, such
as steel or iron.
- High density aggregates are used to produce concrete that has higher than
normal density, usually for radiation shielding or an application where high-
density concrete is needed for counter balancing, ballasting, or stabilizing.
- High density concrete may be used in sound or vibration attenuation and in
improving the abrasion resistance in industrial facilities.
, What is the most important requirement of a concrete aggregate? - correct
answer ✔Aggregate should be resistant to degradation and not undergo
harmful reactions under the conditions to which it will be exposed.
- Deleteriously reactive constituents in an otherwise satisfactory aggregate will
be rendered harmless if used with a portland cement having sufficiently low-
alkali content or if a sufficient amount of pozzolan or slag is used.
- Testing the aggregate with the proposed job materials and considering the
availability of alkalies from outside sources, such as deicing salts, are
recommended
Does the selection of aggregates affect concrete durability? - correct answer
✔Yes. Selecting aggregates that are stable and durable by themselves has
always been a primary requirement for durable concrete.
-Recent developments however, have shown that sometimes aggregates that
are durable by themselves can be deleteriously reactive with alkalies from the
cement or elsewhere.
How can durable aggregates be ensured? - correct answer ✔Durable
aggregates can be ensured by a knowledge of their past performance under
conditions similar to those expected for the structure in question. Where only
new and untried materials are available, examination by a petrographer at the
sources and in the lab, as well as lab tests are justified for important
structures.
What characteristics of the aggregate are of principle concern in affecting the
strength of the concrete? - correct answer ✔- Particle shape, surface texture,
size range of the particles, combination of sizes (grading), and strength and
elastic modulus of the aggregate are important.
- A very high modulus aggregate will contribute to volume stability by increase
brittleness.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller LEWISSHAWN55. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $13.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
78998 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now