AN EXPERIMENTAL STUDY ON STRENGTH AND DURABILITY CHARACTERISTICS OF HIGH STRENGTH CONCRETE MADE WITH PARTIAL REPLACEMENT OF CAST- OFF AGGREGATE

Abstract

Investigate on the convention of waste production materials is extremely significant due to the equipment waste is steadily growing with the improved of residents and increasing of town development. Virgin aggregate need to mine but cast-off aggregate can ignore this process. Whenever cast off aggregate is applied, water content in the concrete mix has to be monitored carefully due to the water absorption capacity of cast off aggregate will vary. The study was carried out in two parts one is fresh and mechanical property of concrete and second one includes durability of concrete. In first part includes workability test, compressive test, direct tensile test, flexural strength and modulus of flexibility test. In the second part includes RCPT and Sorpitivity test. There were total of six batches of concrete mixes, consists of each 10% increase of cast-off aggregate substitute from 0% to 50. Based on the fresh concrete property results it was concluded that the workability of concrete significantly reduced as the amount of cast off aggregate increased. This was evaluated during normal slump test and compacting factor test Based on the observations and experimental work it was concluded that although the values of strength results of cast - off aggregate is lower than the natural aggregate, they are still within the useable range and by limiting the replacement ratio, the desirable strength can be easily obtained using cast - off aggregate concrete also.