Detta examensarbete är baserat på experimentella studier med avsikten att studera skillnaden som uppstår vid användning av superplasticerare på betong med krossad betong samt makadam och sand som ballast, med avseende på arbetbarhet, konsistens samt tryckhållfasthet. Fraktionsfördelningen kommer även analyseras på den krossade betongen i jämförelse med makadamen och sanden. Det utformades fyra olika blandningar där första blandningen var utan superplasticerare och hade makadam som ballast, andra blandningen innehöll superplasticerare samt makadam som ballast, den tredje blandningen var utan superplasticerare och hade krossad betong som ballast, den fjärde blandningen innehöll superplasticerare och hade krossad betong som ballast. Betongens arbetbarhet uppskattades på samtliga blandningar innan konsistensen mättes. Konsistensen mättes i form av sättmått med hjälp av en sättkon. Sedan tillverkades fyra provkroppar av varje blandning där tryckhållfastheten testades. Resultaten som erhållits visade att superplasticerare var mer effektiv på blandningarna med makadam. Betongens arbetbarhet och konsistens förändrades endast marginellt, dock ökade tryckhållfastheten med 28,7 och 23,8% för blandningarna med makadam respektive krossad betong som ballast. Den krossade betongen visade på bra fraktionsfördelning men skiljde sig någorlunda från makadamen, den stora skillnaden fanns i de finare fraktionsstorlekarna. / This thesis is based on experimental studies with the intention of determine the efficiency of Superplasticizer in concrete made with recycled concrete aggregate compared with macadam in terms of workability, consistency and compressice strength. The fraction distribution will also be analysed on the recycled concrete aggregate compared to the macadam. Four different mix designs was made in which the first mix was without superplasticizer and had macadam as aggregates, the second mix contained superplasticizer and also had macadam as aggregates, the third mix was without superplasticizer and had recycled concrete aggregate, the fourth mix contained superplasticizer also had recycled concrete aggregates. The workability of was estimated on all mix designs before the consistency was measured. The slump of all mix designs was measured to determine the consistency. Then four specimens were made from each mixture on which the compressive strength was tested. The results obtained showed that superplasticizers were more effective on the mixtures with macadam as their aggregates. The workability and consistency only changed slightly, the compressive strength increased by 28.7 respectively 23.8% for mixtures with macadam and recycled concrete aggregates. The recycled concrete aggregates showed good fraction distribution but differed quite a bit from the sand and the macadam, the big difference was in the finer fractions.

The following thesis is a comparison study which was performed in cooperation with Sika Sverige AB. The project was to examine concrete’s behaviour while being subjected to different accelerators which is used to speed up the hardening process in young concrete. Sika provided the materials and the instructions for the tests that were made. The tests used where almost like the tests being performed at Sika’s laboratories but with some adjustments to the testing equipment. According to the results of the tests a clear difference between the different accelerators were found. The conclusion that the efficiency of the different accelerators were affected on several variables such as cement type, hardening age and hardening temperature were drawn. Because of the corona outbreak (2020) the tests could not be performed in Sikas laboratories. The tests were therefore carried out at a temporary laboratory without any direct supervision and some professional equipment could not be obtained which resulted in replacements with creative solutions. These changes affected the individual test results with high certainty but should not interfere with the conclusions on account that all test samples were subjected to the same circumstances.