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 ...

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 ...

Near-surface mounted (NSM) bars have been used for flexural strengthening of reinforced concrete members. The data available on this type of reinforcement technique are limited and typically, the bars or strips are embedded using an epoxy. Long term durability, abrasion resistance, and compatibility of the repair are important issues with this type of repair. One untested option for embedding t...

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...

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...

This study investigated the basic mechanical and microscopic properties of cement produced with metakaolin and quantified the production of residual white efflorescence. Cement mortar was produced at various replacement ratios of metakaolin (0, 5, 10, 15, 20, and 25% by weight of cement) and exposed to various environments. Compressive strength and efflorescence quantify (using Matrix Laborator...

introduction: candida albicans (ca) is by far the most common yeast of oral infections, including endodontic infections. the aim of this study was to evaluate and compare the antifungal effect of white-colored mineral trioxide aggregate (wmta) and portland cement (pc) using a tube-dilution test. materials and methods: wmta and pc were tested freshly mixed and after 24 h. the experiment was perf...

A persistent question in industrial economics is the underpinning of the link between market concentration and price. How much of the link can be attributed to market power and how much to market efficiency? This paper develops a theoretical model to address that question. Applied to the US portland cement industry, the model indicates that both impacts matter. In relative terms, however, the m...