chap 2 Flashcards
portland cements set and harden by a process called x
hydration
most pozzolans reduce the x of concrete by filling in the spaces between x particles, and also improve its x
permeability, cement, durability
concrete made without coarse aggregate is usually called x or x
mortar, grout
aggregate is referred to as fine aggregate when it is x mm(in) or smaller
5mm (1/4in)
aggregate properties that affect concrete quality are
maximum size, aggregate size distribution, aggregate shape, moisture in the aggregate, and amount of coarse and fine aggregate in the mixture
aggregate producers may sort aggregates by size, then recombine them in proportions to meet a grading specification. true or false
true
in general, concrete mixtures using aggregates with a x particle size distribution curve will produce the best results
smooth
generally, any water that is x can be used for making concrete
drinkable
seawater may cause x in reinforced concrete
reinforcement to rust
a concrete mixture may be designed using x to change freshly-mixed (plastic) and hardened properties
admixtures
superplasticizers, pumping aids, and air entrainers are examples of
admixtures
an x is defined as any material deliberately added to concrete before or during mixing, other than cement, water, aggregates, and fiber reinforcement
admixture
accelerating admixtures are useful when concreting in x temperatures
cold
x are added to accelerate the set of the shotcrete
accelerators
x are sometimes used in the concrete mixture when temperatures are high when placing concrete
retarders
water reducers are used to x
increase the slump of concrete
air is intentionally entrained in concrete mainly to
increase resistance to damage from freezing and thawing
