This thesis has been developed inassociation with Strängbetong AB, Sweden.A few years backCementa AB introduced a new type of cement on the Swedish market: Byggcement,which is a Portland Limestone Cement. This type of cement is better for theenvironment and cheaper than Rapid Hardening Cement which is used today at SträngbetongAB.Strängbetong AB isvery interested in a change of cement in the factory and wants to know what ittakes to make a transition from Rapid Hardening Cement to Byggcement.This final projectaims at investigating how the workability and strength development are affectedby a transition from the existing cement to Byggcement and how we can change theproperties of the concrete by adding different types of Superplasticizers. Laboratory and factoryexperiments were made, to investigate the transition..

This thesis has been developed inassociation with Strängbetong AB, Sweden.A few years backCementa AB introduced a new type of cement on the Swedish market: Byggcement,which is a Portland Limestone Cement. This type of cement is better for theenvironment and cheaper than Rapid Hardening Cement which is used today at SträngbetongAB.Strängbetong AB isvery interested in a change of cement in the factory and wants to know what ittakes to make a transition from Rapid Hardening Cement to Byggcement.This final projectaims at investigating how the workability and strength development are affectedby a transition from the existing cement to Byggcement and how we can change theproperties of the concrete by adding different types of Superplasticizers. Laboratory and factoryexperiments were made, to investigate the transition..

Concrete is a very common construction material. It´s characteristics are strength, durability and formablility. Superplasticizer is a common admixture, which changes the properties of concrete. Today (spring 2007) there are no certian mathematical methods to calculate the required percentage of this admixture needed to give the necessary set slump flow in the overall concrete recipe. Concrete batching companies must therefor experiment with different amount of superplasticizer in order to meet the specified slump and strength. The purpose og this report is to investigate if any mathematical relation can be established between the amount of superplasticizer used and the slump flow achieved. After carrying out some practical experiments using four different Superplasticizers a direct relationship can be establish between the percentage of admixture used and the slump/flowability achieved. Unfortunatly at present due to the numerous variables, the calculation of mathematical formula can not be achieved..

Vid betongframställning förekommer det spridningar i delmaterialens egenskaper som påverkar den färskaoch hårdnande betongen. Spridningarna i betongens delmaterial har studerats hos tre av Skanskas betongfabriker(Göteborg, Luleå och Norrköping), genom provuttag som analyserats hos Cementa Research.Provuttag har gjorts en gång per månad under ett års tid från fabrikerna. Delmaterialen som har analyseratsär ballast, cement, flytmedel och kalkfiller (endast hos Göteborg och Norrköping). Siktning av ballast0-8 mm har utförts med den traditionella siktningen. För kornstorlekar mindre än 0,25 mm, cement samtkalkfiller har lasersiktning använts.För att få en överskådlig bild över spridningarna hos delmaterialen har en analys utförts som illusteraravvikelserna med exakta siffror.