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Kussande van die Wes-Kaap en die benutting van superfyn-duinsand in beton.

dc.contributor.advisorHugo, F.en_ZA
dc.contributor.authorLoedolff, Gerrit Francoisen_ZA
dc.contributor.otherStellenbosch University. Faculty of Engineering. Department of Civil Engineering.
dc.date.accessioned2012-08-27T12:26:38Z
dc.date.available2012-08-27T12:26:38Z
dc.date.issued1985
dc.identifier.urihttp://hdl.handle.net/10019.1/68521
dc.descriptionProefskrif (Ph.D.) -- Universiteit van Stellenbosch, 1985.
dc.description.abstractENGLISH ABSTRACT: A survey of the Coastal sands along the False Bay coast, the Peninsula and the West coast as far North as Kreeftebay, was made and the physical properties of the sands were determined. With coastal sands is meant the sands in the vicinity of the highest water level and nearer to the sea and that of the dunes close to the sea. Since coastal sands have either an excess or a lack of 0,150 mm particle sizes, a method was sought by which concrete and mortar mixes could be designed. The most difficult part, namely superfine dune sand i.e. sand with a fineness modulus of less than 1.0, was thoroughly investigated. By determining the packing abilities and investigating packing step by step a method by which mixes could be judged by best packing or lowest porosity, was found. With this norm available by which mixes could be judged, grading curves received new attention. It was found that basic grading curves could be very valuable and methods to construct basic grading curves were consequently described. The final overall grading curve of the mix must be balanced around the basic grading curve to obtain best packing. It was also apparent that fine coarse aggregate of 4,8 to 6 mm particle sizes, played a major role when concrete was to be made. Bleeding and bleeding capacities of dune sands were also investigated. External bleeding indicates that something could be wrong with the mix, while internal bleeding is actually the detrimental factor with regard to greater shrinkage and possibly less strength. The most important aspect is therefore to determine the bleeding capacity of the mix and a method is developed to do just that.Shrinkage was also investigated and it was found that shrinkage of superfine dune sand mortar mixes increased as the w/c ratio increased above 0,50. With w/c = 0,50 and less the shrinkage of superfine dune sand mortars was not significantly different from that of normal sand mortars. In conclusion the applications and uses of poorly graded dune sands in the building trade, were discussed. Concrete mixes with dune sands will visually appear to be different from the concrete one is used to. It will have a drier appearance but as long as it is thoroughly compactable to a low porosity one must accept it. All dune sands can be used in the building trade either as concrete bricks or blocks, or for mortar in bricklaying, or for plastering or rendering or for concrete but in some cases aid in the form of coarser or finer sand or of finer coarse aggregates of 4,8 or 6 mm sizes or perhaps of admixtures such as plasticisers, will be needed. Since many of the findings and concepts developed in "Die Rol van Water in Beton"< 12 ) by the author, are used in this work, this publication should be read in conjunction with this thesis.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: 'n Opname is gemaak van die kussande langs die Valsbaai-kus, die Kaapse Skiereiland en van die Weskus tot sever as Kreeftebaai en hul fisiese eienskappe is bepaal. Met kussande word hier bedoel sande in die omgewing van hoogwatermerke en nader aan die see asook die van duine vlak langs die see. Aangesien kussande die eienaardige eienskap het van of 'n tekort of ' n o or ma at sand w at de u r di e O , 1 5 0 mm s if g a an, is me to des gesoek waarvolgens beton en mortel menge ontwerp kan word. Die moeilikste deel, naamlik superfyn duinsand, dit wil s~ sand waarvan die fynheidsmodulus kleiner as 1,0 is, is deeglik ondersoek. Deur verpakkingsvermo@ns te bepaal en verpakking stelselmatig te ondersoek, is 'n metode gevind waarvolgens menge beoordeel kan word deur te soek na beste verpakking en laagste porositeit. Met 'n norm beskikbaar waarvolgens menge beoordeel kan word, is weer gekyk na graderingskurwes. Dit is gevind dat basiese . graderingskurwes wel baie nuttig is en beskrywings van hoe eenvoudige· basiese graderingskurwes opgestel kan word, word verduidelik. Die finale graderingskurwe van die meng, moet nou sodanig wees dat dit balanseer om die basiese kurwes. Dit blyk ook dat fyn growwe aggregaat soos 4,8 mm of 6 mm klip 'n uiters vername rol speel en veral wanneer beton gemaak moet word. Vervolgens is ook gekyk na bloei en die bloeivermo~ van duinsande. Eksterne bloeiing toon dat iets moontlik met die meng skort, terwyl interne bloeiing die nadelige element is wat krimping vergroot en sterkte kan verlaag. Die belangrikste is egter dat die totale bloeivermo~ van 'n meng vasgestel word en 'n metode is ontwikkel om juis dit te doen. Daarna is ook gekyk na krirnping en gevind dat mortels van superfyn duinsand se krimpverrno~ vergroot soos die W/s verhouding groter word as 0,50. Met w/s = 0,50 en kleiner, is die krimpvermo~ van duinsandrnenge nie beduidend verskillend van die van gewone sandmenge nie. Ten slotte is ook gewys op die toepassings en gebruike van swakker gegradeerde duinsande in die boubedryf. Betonmenge sal byvoorbeeld anders lyk as die waaraan 'n mens gewoond is orndat hul voorkorns baie 'droog' kan wees, rnaar tog goed verdigbaar mag wees. Alle duinsande kan gebruik word of vir die rnaak van betonstene of -blokke, of vir rnesselwerk, of vir pleisterwerk of vir beton, rnaar in sornrnige gevalle sal hulp nodig wees in die vorrn van 'n growwer of fyner sand of fyner aggregaat van 4,8 of 6 mm grootte of selfs van bymengsels soos plastiseerders. Aangesien hierdie werk gebruik maak van heelwat begrippe en bevindings wat ontwikkel is in "Die Rol van Water in Beton"(12) deur skrywer rnoet genoemde publikasie saam met hierdie proefskrif gelees word.af_ZA
dc.format.extent1 v. (verskeie paginerings) : ill.
dc.language.isoaf_ZA
dc.publisherStellenbosch : Stellenbosch University
dc.subjectSand dunes -- South Africa -- Western Capeen_ZA
dc.subjectConcrete -- Mixingen_ZA
dc.subjectSanden_ZA
dc.subjectDissertations -- Civil engineeringen_ZA
dc.subjectUCTDen_ZA
dc.titleKussande van die Wes-Kaap en die benutting van superfyn-duinsand in beton.af_ZA
dc.typeThesis
dc.rights.holderStellenbosch University


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