Presented By:Presented By:Engineer LATIF HYDER WADHOEngineer LATIF HYDER WADHOMehran University of Engg: & Technology KhairpurMehran University of Engg: & Technology KhairpurCivil Engineering MaterialsCivil Engineering Materials11ststTerm 1Term 1ststYear B.E.CivilYear B.E.Civil
DISTEMPERDISTEMPERThese are paints used for the treatmentof masonry walls. In distempers waterinstead of oil is used as a carrier. Theseare also known as water paints. It ismade by mixing whiting and glue boiledin water is known as the size. In market anumber of distempers are available. Allprepared distempers are mixed withwater only before being used. As thedistemper is affected by weather andcomes off, if washed, so is use isrestricted only to interior works.
It forms a cheap, durable and easy finish for interiors.These should be applied in dry weather after thesurface has been cleaned and dried.There are some points which should be kept in mindwhile applying distempers.The surface should be completely dry, there shouldbe no patches of efflorescence, also surface shouldbe smooth, if not surface should be smoothening withsand paper.Old surface should be cleaned properly.These may be applied in two or more coats also.On drying of primary coat (1st), prepared distempersolution in water is applied on the surface with brush.
ADHESIVESIt is a substance that binds two or moresurfaces together. Some times it can bebetter substitute for welding/riveting.Adhesive may be applied by brushing,spraying, etc. Before applying theadhesive the surfaces should be cleanedof all oils, grease, dirt, etc.
Adhesives can join a variety of surfaceslike wood, glass, metals and plastic etc.Adhesives applied joints may beimpervious to gases and liquids. However adhesives can not be used to allmaterials and also choice of adhesivedepends upon the nature of material tobe jointed. It takes time to gain strength.Joints made with adhesives loose theirstability at high temperatures.
Adhesives are either glues or resins.(i) Glues: Glues are derived from animals orfrom vegetables. Animal glues are derived fromdifferent parts like hides or bones of animals.These are prepared by boiling in water horns,hoofs, bones or skins of animals. Animal gluesare prepared from blood and eggs too. It isavailable in the forms of flakes, granules, cakesand jelly.Animal glues are easy to apply and are strongerthan vegetable glues but are nor resistant tomoisture and fungus.Vegetable glues are mostly used in wood etc.
(2) Casein glues: Casein glues areobtained from milk, curd, and lime givesstrong water proof wooden joints whichwithstand weathering well. These glues aremostly used in ply woods.(3)Starch: Starch is derived from corn,wheat and potatoes etc are used in paper,etc.(4)Gum Arabic: Gum obtained fromacacia tree and is soluble in water and ismostly use din tropical areas for paperpacking etc.
(5) Soyabean protein: Soyabean protein isderived from Soya seed and is reasonablygood for use with ply woods.(6) Zein: Zein is product of corn and ischeap and may be used with other adhesives.Resins: Glues may be from natural resins orfrom synthetic resins.Glues from natural resins are like rosin,shellac and asphalt.
(7) Synthetic resins: Synthetic resinsare either thermosetting resins (theseare formed polyesters, epoxies and siliconresins, these are good to withstand hightemperature and resist moisture also) areused in plywood, glass, ceramic bondingand for bonding metallic componentsor thermoplastic resins (such as vinyls,polyvinyl acetate) do not resist moisture orheat and become soft on heating.