Formative MCQ weekly assessments Flashcards
A - Fly Ash
C - 1400
C - Reacts with water
B - Steel
D - A coarse aggregate particle
C - 1.6 tonnes
B - The coefficient of thermal expansion of steel is about the same as concrete
C - It is required for infrastructure development
A - To address concerns over chrome 6 content
A - Coarse aggregate, fine aggregate, cement, water
A - It’s not a very specific test - it’s really for quality control - but probably yield stress rather than plastic viscosity
A - Fluidity, Compatibility, and Cohesion
A - This fraction gives the mix cohesion i.e prevents segregation of the aggregate, cement and water
A - g = yield stress h = plastic viscosity
A - Fine and coarse aggregate sizes; aggregate grading (%<600 microns); crushed vs uncrushed aggregate; cement type
A - Ettringite
A - The period of slow hydration
A - 1.7
A - Ettringite - portlandite - C-S-H
A - C3A
A - Long thin needles
D - Within the volume of the original cement particles
A - 28 days
A - Yes choosing the wrong the wrong aggregate can cause an alkali aggregate reaction which weakens the concrete
A - Docklands light railway
C - It increases by 10-15%
A - They can produce stronger concrete
A - They allow rapid overbuilding on large buildings
A - GGBS (Ground granulated blast furnace slag)
A - They accelerate hydration, enabling more rapid construction
A - C3A (Alite)
A - To obtain good chloride resistance
A - Particles are spherical
A - Oven dried aggregate will be stronger and less workable
A - The fine aggregate fills the gaps between the coarse aggregate particles, reducing voids ratio and thus the amount of cement paste required for compaction
A - Reduced carbon footprint
A - All the reasons
A - Fly ash
A - Quartz undergoes an expansive phase change at 573°C causing the concrete to become unstable.
A - Affects the density of concrete, and hence it’s self weight and deflections
A - Metakaolin
A - How much aggregate will absorb moisture and will also affect porosity
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