Types of Concrete, admixtures, footings

slump test

determines concrete workability, plasticity, determined by water content, air content, admixtures, temp, aggregate properties

air entrainment

how much air is in the concrete; prevents failure during drastic temp changes

compressive strength test

concrete cylinders poured and strength tested in a 28-day span. By 7 days they should be 60-70% the 28th day strength

type I cement

general purpose

type II cement

used where reduced heat of hydration is needed (where things heat up fast)

type III cement

high early strength

type IV cement

low heat of hydration cement; used in large structures

type V

sulfate-resistant; used in soil for coastal communities

fly ash

reacts w/ calcium hydroxide & forms binding agent; used in replacement of portland cement

water cement ratio

the less water in the cement, the stronger & more durable it is- better quality

aggregates

good filler material; requires less cement, more economical

superplasticizers

increase slump while keeping strength; alternative to water

accelerators

shortens setting time; used in cold weather

retarder

extends setting time; used in hot weather

what is max delivery time from concrete being mixed to being poured

90 minutes; 60 minutes is ideal

what is the revolution limit in mixing drum

250 revolutions

isolated footing

designed to support an individual column on a building

wall footing

continuous footing along wall w/ width longer than wall thickness

pile cap

bears deep into soil on rock strata to be structurally sound

combined footings

two concrete footings to support one load

how many parts are in a masonry arch

11

what determines the load required for a building

the weight and shape of form work