Two polycarboxylate ether copolymers were assessed as superplasticizers (SPs) for hydrated lime pastes modified with two reactive compounds, nanosilica (NS) and ceramic metakaolin (MK). Characterization of the molecular structure of the SPs by Size Exclusion Chromatography, XRD, FTIR and MALDI-TOF (Matrix Assisted Laser Desorption Ionization Time-of-Flight) mass spectrometry was performed. The ...

Geopolymers are generally appreciated for their good resistance against high temperatures. This paper compares the influence of thermal treatment with temperatures ranging from 200 to 1200 °C on the mechanical properties and microstructure of geopolymers based on two different aluminosilicate precursors, metakaolin and fly ash. Moreover, the paper is also aimed at characterizing the effect of c...

Neural networks have recently been widely used to model some of the human activities in many areas of civil engineering applications. In the present paper, artificial neural networks (ANN) for predicting compressive strength of cubes and durability of concrete containing metakaolin with fly ash and silica fume with fly ash are developed at the age of 3, 7, 28, 56 and 90 days. For building these...

background: this study was conducted to determine the species of oral and non-oral microorganisms in dental laboratory pumice in order to undertake the necessary disinfection control protocols. methods: fourteen active and well-known dental laboratories of tehran entered our study. samples of pumice were collected from polishing containers in a completely sterilized and controlled condition. th...

The geometry of mesoscopic single and multiple layer folds in rhyolitic obsidian ̄ows is investigated. Folds are composed of obsidian embedded in a matrix of pumice. Folds form by buckling processes as indicated by discontinuous deformation between obsidian and pumice layers and by the geometries of wavetrains. Buckling occurs through a continuum of styles controlled largely by the thickness ra...

Alkali activated material has recently attracted great attention as an environmentally friendly building material. Generally, it exhibits higher mechanical properties and better durability when compared with Portland cement based materials. In this article, mixed alkali activated systems consisting of N-A-S-H and C-A-S-H hydrated gels were produced, using metakaolin as a dominated starting mate...

Wastewater treatment of some heavy metals was carried out by synthetic zeolite P1, which was prepared by alkaline hydrothermal treatment of the pumice. Both of the pumice raw materials and synthetic zeolite were investigated for their chemical phase composition, physical properties, and microstructure. The adsorption behavior of Na-zeolite P1 with respect to Co(+2), Cu(+2), Fe(+2), and Cd(+2) h...

BACKGROUND In recent years, proficient treatment of wastewaters containing recalcitrant and toxic compounds such as phenol has been a challenge. This study introduced and evaluated an efficient option for treating such wastewater. METHODS This experimental study was performed on phenol removal as a recalcitrant and toxic compound in aqueous solutions in 2011. The pumice stone was collected fr...