Yazar "Azez, Oday Ali" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Effect of nano silica on the workability of self-compacting concretes having untreated and, surface treated lightweight aggregates
    (ELSEVIER SCI LTD, 2016) Guneyisi, Erhan; Gesoglu, Mehmet; Azez, Oday Ali; Oz, Hatice Oznur
    This paper presents the fresh properties of self-compacting lightweight aggregate concrete (SCLC) made with cold bonded fly ash (FA) lightweight aggregate (LWA) at a wide range of water-to-binder (w/b) ratios. For this, three concrete series including eighteen SCLCs were designed with w/b ratios of 0.25, 0.37 and 0.50, respectively. Each series have 6 different mixes in which two type of coarse LWAs (surface treated or not) and three nano silica (nS) replacement levels (0, 2.5% and 5.0%) are considered. The properties of SCLCs were observed in terms of slump flow diameter, T-500 slump flow time, V-funnel flow time, and L-box height ratio. The compressive strength test was also conducted to obtain the strength level at 28 days. It is found that the fresh SCLCs have good fluidity, passing ability, uniform aggregate distribution and resistance to segregation. Incorporating treated coarse LWA5 increased the workability characteristics of SCLCs. However, appreciable improvement in the consistency of SCLCs by nS addition was observed. The SCLCs made with treated LWAs and 5% nS were found to be the harder samples in this research. (c) 2016 Elsevier Ltd. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Physico-mechanical properties of self-compacting concrete containing treated cold-bonded fly ash lightweight aggregates and SiO2 nano-particles
    (ELSEVIER SCI LTD, 2015) Guneyisi, Ethan; Gesoglu, Mehmet; Azez, Oday Ali; Oz, Hatice Oznur
    In this experimental study, the physico-mechanical properties of self-compacting lightweight aggregate concrete (SCLC) containing artificial lightweight aggregate (LWA) made from fly ash (FA) through cold-bonded process are investigated. Coarse LWAs were treated with a soluble solution of sodium silicates (WG) in order to enhance quality. However, the binary and ternary use of fly ash (FA) and silicon dioxide nanoparticles (nS) were considered in the production of SCLC. For this, a total of 18 SCLC mixtures were designed at three different w/b ratios of 0.25, 0.37 and 0.50, and total binder contents of 600, 550 and 450 kg/m(3), respectively. The physical properties were tested for water sorptivity, gas permeability and water permeability, as well as for drying shrinkage. The use of treated instead of untreated LWA reduces the negative effect of w/b ratio increment of the drying shrinkage of SCLCs. The results showed that using 5.0% nano-silica and treated aggregate decreased the drying shrinkage as much as 23%. However, a significant reduction in SCLC permeability was achieved by including nS and/or treated LWAs, specifically, a reduction of up to 70% for gas permeability at 90 days. Moreover, a lower compressive strength resulted due to the use of untreated aggregate and higher w/b ratio. As a general result, it was determined that a better performance is revealed at 90 days for SCLCs containing 5% nS and treated LWAs, regardless of w/b ratio. (C) 2015 Elsevier Ltd. All rights reserved.