In this research, two series of ultra-low cement high alumina refractory castables containing 0 and 0.4 wt.% of nano-titania were prepared using different amounts of polycarbonic acid (DOLAPIX FF 26) as a dispersant. Several characteristics including microstructure, flowability, mechanical strength, bulk density and apparent porosity of the samples were analyzed. The results showed that the opt...

Colloidal silica bonded refractory castables have been developed recently. It was found that colloidal silica is one of the best binders can substitute other binders such as cement in No Cement Castable (NCC) and Ultra Low Cement Castable (ULCC) refractories. Also composition of colloidal silica with appropriate additives resulted in a gel form which makes the initial strength. Moreover, the na...

We investigate the performance of graphene oxide (GO) in improving mechanical properties of cement composites. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1-2 wt% GO and 0.5 wt% superplasticizer was measured and compared with that of cement prepared without GO. We found t...

introduction: in the kindling-induced seizure model, low and repeated electrical or chemical stimulations, can elevate the neural network excitability and induce epileptiform seizures. opioid receptors are widely distributed in different areas of the brain. on the other hand, morphine has paradoxical effects and induces elevation or alleviation of the pain sensation and excitability, at differe...

Herein, the performance of graphene oxide (GO) in improving mechanical properties and subsequently reducing the permeability of cement composites used in concrete pavement, is studied. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1–2 wt% GO and 0.5 wt% superplasticizer was...

Tricalcium-silicate and Tetracalcium-phosphate were prepared from ultra-pure chemical compounds via solid-state reaction at 1450 o C and 1500 o C respectively in an attempt to formulate a root end filling cement. Materials were investigated by X-ray diffraction and Transmission-electron microscope. The formulated cement comprises 60 wt% Tricalcium-silicate, 20 wt% Tetracalcium-phosphate and 20 ...

It has long been known that temperature during circulation and after cement placement is one of the most important parameters for slurry design and the success in cement production. Conventional cements and low density cement slurries usually take a long time to set and cannot provide significant compressive strength. Therefore, it is important to design appropriate low density cement slurries ...