Abstract Self compacting concrete (SCC) is a new construction material in the world. The aim of this research is to construct self compacting concrete with high compressive strength using combination of nano silica and micro silica. For this purpose, nano silica, micro silica, Portland cement type 2, superplasticizer (SP), and gravel and sand have been used. Three different groups of samples wi...

In this study two series of self compacting concrete mixtures were prepared with 100% coarse recycled concrete aggregates and different percentages of 0%, 20%, 40%, 60%, 80% and 100% fine recycled concrete aggregates. In series I and II the water to binder ratios were 0.50 and 0.45, respectively. The cement content was kept 350 3 m kg for those mixtures that don't have any Nano-Silica. To impro...

in this investigation, nano silica chloride (nano sio2cl) has been found to be efficient, chemoselective and recyclable catalyst for facile and simple synthesis of germinal diacetates from aromatic and heteroaromatic aldehydes in shorter reaction durations. the products were obtained in high to excellent yields. this work consistently has the advantages of excellent yields, short reaction time,...

Silica nanoparticles were synthesized by chemical methods from tetraethylorthosilicate (TEOS), polyethylene glycol 5% and hydrochloric acid 0.001 N. The sol-gel process was applied for the preparation of nano silica gel. This method is hydrolysis and condensation reactions of TEOS as precursor of silica. The optimal synthesis conditions for the preparation of silica nanoparticles were obtained ...

Multi-mode universal adhesives (UA) are indicated as either self-etch or etch-and-rinse adhesives, and manufacturers also recommend an alternative ‘selective enamel etch’ technique. Currently available laboratory data support phosphoric acid selective etching of enamel prior to use of UA to improve bond strength. In another way to improve adhesion to enamel of UA without the use of phosphoric a...

AIM To evaluate and compare ex vivo the decalcifying effect of 15% EDTA, 15% citric acid, 5% phosphoric acid and 2.5% sodium hypochlorite on root canal dentine. METHODOLOGY Two 2-mm-thick slices were cut from the coronal third of the root of 10 human incisors. Each slice was sectioned into two equal parts. Specimens were assigned to one of four groups (n = 10) for immersion in 20 mL of either...

in the recent years, rapid growth of the world’s population and overutilization of fresh water resources have caused fresh water shortage crisis in the world. in spite of the agricultural activities in the northern beaches of iran and also severe decrease of the ground water level, it still has not taken any effective measures to desalinate caspian sea water in large scale. in this research, de...

The self-assembly and sol-gel polymerisation of novel alkoxysilane-functionalized polymethylsiloxanes provide versatile access to nano-assembled containers, silica-based micro- and nano-architectures and dispersed mixed metal oxide hybrid materials.