Second Half Flashcards
(21 cards)
Describe how a retaining wall works
Are designed with basic function of resisting the lateral pressure exerted by the soil and moisture
What’ is a pile cap
It is used to tie the heads of a group of piles together, act as a base for the superstructure and provide an even base to work from
What is the definition of angle of repose
Is the steepest angle if descent and dip relative to the horizontal plane to which a material can be piled without slumping
List 4 different materials used for retaining walks
Timber logs
Masonry
Brickwork
In situ concrete
List 4 different types of retaining walls
Gravity
Cantilever
Crib
Diaphragm walls
What are the main raw materials of cement
Calcium
Silica
Alumina
Iron
Describe the process of hydration
It’s a chemical reaction in which water combines with the various constituents of cement
What is the time for initial set according to the AS
Initial setting before 60 mins final setting within 12 hours
Why does so much water in the cement mix weaken the mix
Excess water will was the cement out
Describe the curing and at what’s temperature does hydration stop
Process in which concrete is protected from loss of moisture and keep within a reasonable temperature range , stop at 0C
What does tri-calcium aluminate do in cement
Has a very high rapid of hydration , contributes in setting and early hardening of cement
What’ does tri-calcium silicate do in cement
Hydrates at a moderately fast rate and contributes in initial and final setting
What does tetra calcium alumina ferrite do in cement
Affects the setting and early early strength because of it’s rapid hydration
Describe what masonry cement are
Contains Portland cement and limestone and used for masonry mortar
Describe cement
Mixer of cement
Water
Coarse
And fine aggregates
List 5 points that’s effects the compressive strength in concrete
Water Density Age of concrete Type of cement Curing conditions Cement ratio
Describe what tensile strength in concrete
A measure of the ability of concrete to hold together
List 3 types of vibration in concrete
Immersion
Form
And surface vibration
What can over vibration cause in concrete
Form damage
Concrete separation
And cracks
Describe aerated concrete and list 3 points
Various Method have been used for producing the aeration of the concrete mix
- processes in which gas is produced by chemical reaction
- processes in which foam - producing substance is added to the mix to introduce and stabilise air bubbles
- process involving the use to excess water
List 4 characteristics of concrete
Plastic mouldable when fresh
High compressive strength when hard
Low tensile strength
High resistance to fire
