نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری، دانشکده مهندسی عمران، دانشگاه سمنان
2 استاد، دانشکده مهندسی عمران، دانشگاه سمنان
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Rheological properties of Self-compacting concrete are important in saving time and cost. The aim of this research was to investigate the effect of adding iron slag with two different specific surfaces (the first type was normal iron slag with a specific surface of 3800 blaine and the second type was fine iron slag with a specific surface of 6000 blaine) on the rheological and strength properties of self-compacting concrete. Ten concrete mixes including control mix and nine mixes containing three compositions of iron slag were designed with proportions of (20-30-40) percent of cement weight. The first composition of slag consists was 100% normal slag, the second was 75% normal slag and 25% fine slag, and the third one was 50% normal slag and 50% fine slag. The J-ring test (to measure the flow diameter, T50 time, and the height difference of the concrete in the middle and outside of the ring ) and the V-funnel test (to measure the V-funnel time) were performed for fresh concrete. The compressive and tensile split strengths were performed to measure the strength properties of hardened concrete. The results of the J-ring test indicated that the flow diameter was decreased for concretes with each composition of slag, the mixtures containing 30 and 40% of third composition of slag had a decrease of 2.5 and 3.1%, respectively, while the T50 results compared to the control mix showed an improvement and the mixtures containing 20 and 30% of first composition of slag had a decrease of 53 and 47%, respectively. Regarding the difference in height of the concrete between the middle and outside of the ring, the results indicated an increase in height when adding any composition of slag and the mixtures containing 30 and 40% of third composition slag were increased by 76 and 69%, respectively. The V-funnel test showed variation in the results that the addition of 20 and 40% of first composition of slag resulted in a reduction of the V-funnel time by 12 and 11%, respectively. The two different slags with specific surfaces had different effects on flow diameter, T50, Δh and V-funnel time. The results of the 28-day compressive strength test indicated an increase in compressive strength when 30 and 40% of third composition of slag were added, with a ratio of 12 and 15%, respectively. However, the results of the 28-day tensile split strength test have shown that the addition of 30% of third composition of slag leads to an increase in tensile strength by 8%. The second and third compositions contain slag with a specific surface of 6000 blaine respectively 25 and 50% of the weight of each composition, this leads to an increase in the rate of hydration reaction more than that in the first composition. Therefore, the compressive and tensile strengths increases compared to the first combination.
کلیدواژهها [English]