AND SOLUTIONS RATED A+
✔✔Advantages of Plural component spray over single component spray - ✔✔Accurate
mixing without human element, sprays very thick solvent free materials without thinners
& sprays materials with very short pot life.
✔✔2 major classes of rubber - ✔✔natural and synthetic
✔✔Natural rubber - ✔✔derived from latex from Hevea trees, and coagulated with acetic
or formic acid. Unsaturated hydrocarbon (polyisoprene)
✔✔Synthetic rubber - ✔✔1 or more properties of natural rubber and any one of a group
of man-made elastomers.
✔✔Vulcanization - ✔✔Physicochemical change from cross linking the unsaturated
hydrocarbon chain of natural rubber with sulfur and applying heat
✔✔3 factors the affect the properties of vulcanized products - ✔✔% of sulfer and
accelerator used, temp during curing process and time of cure.
✔✔Methods used to volcanize rubber - ✔✔Autoclave, internal steam cure, exhaust
steam cure (atmospheric) hot water cure and chemical cure
✔✔Categories of Natural Rubber - ✔✔Soft, semi hard and hard
✔✔Tri-ply lining - ✔✔Sandwich of semi-hard/hard rubber between 2 layers of soft
rubber
✔✔Synthetic rubber types - ✔✔Butyl rubber, Neoprene rubber, Nitrile rubber,
Chlorobutyl rubber, Hypalon
✔✔Cause of failure on Rubber linings - ✔✔Incorrect product selected, using after shelf
life expired, not correctly storing rubber, incorrect application process and inadequate
cure.
✔✔Applying polyethylene - ✔✔Melt the resin and extrude it onto the surface, heat the
work piece and immersing it into a fluidized bed or flamespraying
✔✔SES - ✔✔Standard Engineering Society
✔✔Voluntary standard - ✔✔established by private sector bodies and available for use
by any person or organization (private or gov't)
, ✔✔Mandatory standard - ✔✔requires compliance because of gov't statue or regulation,
internal policy or contractual requirement
✔✔National Standards Body (NSB) - ✔✔1 per country member of ISO
✔✔Standards Developing Organization (SDO) - ✔✔thousands of industry or sector
based standard organization that develop and publish industry standards. (ie NACE)
✔✔3 NACE classifications - ✔✔SP standard practice, TM test methods, MR material
requirements
✔✔Concrete cures by - ✔✔Hydration
✔✔Poured concrete can be affected by - ✔✔Ambient conditions & vibrations
✔✔Guniting - ✔✔process of spraying or slinging shotcrete onto a surface as a coating
to restore concrete to its original grade.
✔✔Reasons to coat concrete - ✔✔decoration, waterproofing, enhance chemical
resistance, protect from freeze- thaw cycle, protection from reinforcing steel,
decontamination, surface sealer, protection against abrasion and erosion, color coding,
protecting products contained, improving or simplifying cleaning, skid resistance
✔✔Laitance - ✔✔weak surface layer of WATER rich cement mix on the surface of fresh
concrete caused by upward movement of water.
✔✔Efflorescence - ✔✔Moisture passing through concrete carrying soluble SALTS to the
surface. Salts react with CARBON DIOXIDE in atmosphere . White fluffy crystalline
deposits.
✔✔Concrete surface prep - ✔✔abrasive blast cleaning, hand/ power tool cleaning, high
pressure waterjetting/ blasting, acid etching, stoning, centrifugal blasting or scarifying
✔✔NACE 6/ SSPC SP 13 - ✔✔Standard for Surface prep of Concrete
✔✔Advantages of waterjetting/ wet abrasive blasting on concrete - ✔✔fast cutting of the
surface, washing dust away, reduces particles in the air.
✔✔Sacking - ✔✔scrubbing a mixture of cement mortar over the concrete using sack,
sponge rubber float
✔✔Stoning - ✔✔abrasive block is used to smooth the surface of concrete