In this paper, the correlation of reflection loss measured by an ultrasonic shear wave reflection method and the microstructure in cement-based material is investigated. Three cement pastes (Portland cement type I) with different water-cement ratios (0.35, 0.50 and 0.60) cured at 25 °C were examined. The ultrasonic shear wave reflection factor (WRF) was measured by the wave reflection technique...

Physicochemical properties of pozzolan Portland cement were compared to ProRoot MTA and MTA BIO. To test the pH, the samples were immersed in distilled water for different periods of time. After the pH analysis, the sample was retained in the plastic recipient, and the electrical conductivity of the solution was measured. The solubility and radiopacity properties were evaluated according to spe...

OBJECTIVE The levels of 10 heavy metals (arsenic, bismuth, cadmium, chromium, copper, iron, lead, manganese, nickel, and zinc) in gray Portland cement (GPC), white Portland cement (WPC), gray MTA (GMTA), and white MTA (WMTA) were analyzed by inductively coupled plasma-atomic emission spectrometry (ICP-AES). STUDY DESIGN One gram of each material was digested with 80 degrees C "aqua-regia" (7 ...

Calcium silicate hydrate (CSH) is the main binding phase of Portland cement, the single most important structural material in use worldwide. Due to the complex structure and chemistry of CSH at various length scales, the focus has progressively turned towards its atomic level comprehension. We study electronic structure and bonding of a large subset of the known CSH minerals. Our results reveal...

Over the vast Northwest China, arid desert contains high concentrations of sulfate, chloride, and other chemicals in the ground water, which poses serious challenges to infrastructure construction that routinely utilizes portland cement concrete. Rapid industrialization in the region has been generating huge amounts of mineral admixtures, such as fly ash and slags from energy and metallurgical ...

INTRODUCTION Perforations of the pulpal floor create problems during endodontic treatment and often results in secondary periodontal involvement with eventual loss of teeth. The purpose of this study was to evaluate the ability of mineral trioxide aggregate (MTA), Amalgam, zinc oxide and eugenol (ZOE) and Portland cement to seal furcal perforations in extracted human molars using dye penetratio...

It is demonstrated that the addition of organo-modified Na-bentonite (OMB) particles to Portland cement mortar can promote its physical and mechanical properties. A series of experimental works on some important physico-mechanical properties of Portland cement mortars mixed with various dosages of hydrophobic OMB were performed. The obtained results confirm that the OMB provides a dense packing...

The use of cement and concrete to immobilise radioactive waste is complicated by the wideranging nature of inorganic cementing agents available as well as the range of service environments in which cement is used and the different functions expected of cement. For example, Portland cement based concretes are widely used as structural materials for construction of vaults and tunnels. These const...

OBJECTIVE To characterize the hydration products of white mineral trioxide aggregate (MTA). METHODOLOGY Mineral trioxide aggregate, white Portland cement and bismuth oxide were evaluated using X-ray diffraction (XRD) analysis and Rietveld XRD. The cements were tested un-hydrated and after hydration and curing for 30 days at 37 degrees C. Analysis of hydrated cement leachate was performed week...

Sulfate attack is potentially one of the most damaging forms of degradation affecting portland cement-based materials. However, despite over six decades of study, considerable uncertainty remains in optimally selecting and proportioning materials for sulfate resistance, and current understanding of the actual mechanisms of degradation in sulfate environments remains incomplete. In this research...