Mahdi Mahdikhani - Assistant professor, Civil Engineering Department, Faculty of Engineering, Imam Khomeini International university, qazvin, Iran
Seyyed Naser Amini - Civil Engineering Department, Faculty of Engineering, Imam Khomeini International University Qazvin, Iran
Hamid Bayat

This paper reports the effects of Nano Silica (Ns) and Silica Fume (SF) on the rheology, compressive strength and aggregate segregation of Self Consolidating Lightweight Concretes (SCLC).Totally, sixteen concrete mixtures are prepared containing different amounts of SF and NS as 0%, 2% and 6% (by weight of cement) with water/binder (W/B) ratios of 0.44 Fresh properties of concretes were determined through Visual Stability Index (VSI), slump-flow time and diameter and V-funnel flow time (T0min and T5min) tests, In addition, the uniformity of distribution of LWAs along the specimen is also evaluated by the column segregation test and the crow-section image. The results showed that the fresh properties of SCLC improved significantly for the specimens containing micro and Nano silica. The results indicate that the mixtures containing NS and SF have higher viscosity than the control mixture, Furthermore, although in some specimens the compressive strength of the concrete mixtures had slightly increase, aggregate segregation and uniformity of distribution of LWAs were enhanced by using silica, especially in Nano scale.

Self-Consolidating Lightweight Concrete, Rheological Properities, compressive Strength, Segregation Resistance, Silica fume, Nano-SiO2