Nano-SiO

TABLE 5.2 The properties of nano-SiO, used in this experiment. 

The absorption characteristics indirectly represent the porosity through an understanding of the permeable pore volume and its connectivity. In order to investigate the effect of nano-Si02 particles on cement mortar permeability, a water absorption test was carried out on various mixtures A-1 (plain cement mortar), A-5 (cement mortar with 7% nano-SiO ), A-7 (cement mortar with 20% RHA replacement) A9 (cement mortar with 20% RHA replacement and 3% nano-SiO ). The final absorption of these mixtures are shown in Table 5.4. It can be seen that mixture A-5 (cement mortar with 7% nano-SiO ) showed the lowest absorption of all the mixtures which shows that nano-SiO is more effective in reducing the permeability than RHA. Integrating nano-SiO into RHA mortar reduced the water absorption from 5.42% to 4.45%. Results showed that the presence of nano-SiO particles in cement mortar could decrease the water absorption and the likely permeability of cement mortar. This impermeability increase can be attributed to two concomitant phenomena ... 

FIGURE 5.3 Shrinkage of mortars containing nano-SiO versus time. 

Cement paste characteristics, for example, strength and permeability significantly depended on its nanostructure features in particular nanoporosity. In recent years, electron microscopy has been demonstrated to be a very valuable method for the determination of microstructure. Numerous studies on the influence of nano-SiO on the microstructure of plain cement mortar have been carried out. The results showed that nano-SiO particles formed a very dense and compact texture in the hydrate products and decreased the size of big crystals such as CH. In this chapter in order to study the microstructure of RHA mortar, with and without nano-SiO, a SEM was used. The microstrueture of the RHA mortar with 3% replacement of nano-SiOj and without nano-SiO at a euring age of seven days are presented in Fig. 5.5 and Fig. 5.6, respeetively. Results showed that the nano-SiOj particles improved the dense and compact microstructure of RHA and generated a more homogenous distribution of hydrated products. 

X. Liu, Y. Zou, G. Cao, D. Luo, The preparation and properties of biodegradable polyesteramide composites reinforced with nano-CaCOj and nano-SiO, Mater. Lett. 61 (2007) 4216-4221. 

The influence of nano-Al Oj and nano-SiO particles on altering the thermal degradation behavior of the imsaturated polyester-based composite system under various testing environments (Nitrogen and air) is shown in Table 9.6. 

Similar increases in carbonyl index, vinyl index and crystallinity have also been reported for rape straw flom (RSF)/HDPE and nano-SiO /RSF/ HDPE composites exposed to natural weathering for 120 days by Zuo et al. [61]. 

Preyssler Heteropolyacid Supported on Nano-SiO, Hj pSlaPjWjjOjjJ/SiOj ... 

S. Tang, P. Zou, H. Xiong, H. Tang, Effect of nano-SiO on the performance of starch/poly-vinyl alcohol blend films, Carbo. Polym. 72 521-526,2008. 

Zhang et al. [115] reported the change of phase morphology and properties of immiscible PP/PS blends compatibilized with nano-SiO particles. The compatibility of PP/PS blends was dramatically improved with the addition of nano-SiO particles, which possess excellent hydrophobicity and contain a large number of alkyls on their surfaces. The SiO content and mixing time also had profound effects on the compatibility of PP/PS blends. A drastic reduction of PS phase size and a very homogeneous... 

Zhang Q, Yang H, Fu Q. Kinetics-controlled compatibUization of immiscible polypropylene/polystyiene blends using nano-SiO particles. Polymer 2004 45 1913-22. 

---