introduction: the aim of the present study was to evaluate the biocompatibility of two modified formulations of portland cement (pc) mixed with either titanium oxide or both titanium oxide and calcium chloride. methods and materials: polyethylene tubes were filled with modified pcs or angelus mta as the control; the tubes were then implanted in 28 wistar rats subcutaneously. one tube was left e...

This study investigated the solubility of mineral trioxide aggregate (MTA) and Portland cement since its mixture until 672 hours, by means of two complimentary methods. Metal ring molds filled with the cements were covered with distilled water and, at each experimental time (3, 24, 72, 168, 336 and 672 hours), were weighed as soon as the plates in which the samples have been placed. Empty rings...

Objective. The aim of this study was to evaluate the antimicrobial activity and pH changes induced by Portland cement (PC) alone and in association with radiopacifiers. Methods. The materials tested were pure PC, PC + bismuth oxide, PC + zirconium oxide, PC + calcium tungstate, and zinc oxide and eugenol cement (ZOE). Antimicrobial activity was evaluated by agar diffusion test using the followi...

BACKGROUND One ideal property of a root-end filling material is its apical sealing ability. The aim of this in vitro study was to assess bacterial and dye microleakage of white and gray mineral trioxide aggregate (WMTA and GMTA), Portland cement and calcium-enriched mixture (CEM) cement used as root-end filling material, and to assess the agreement between these two test methods. MATERIALS AN...

In the cellulose industry the Kraft process is widely used to produce cellulose. This process generates huge volumes of inorganic solid wastes, including the grits waste. In Brazil, the final disposal of this solid waste is of high economical and environmental interest. The present work assesses the influence of the addition of grits waste on the densification behavior of soil-cement bricks. Th...

Stephen S. Szoke, P.E., LEED/AP, FACI Director, Codes and Standards Portland Cement Association 5420 Old Orchard Road, Skokie, IL 60077 +1-847-972-9078 [email protected] Stephen V. Skalko, P.E. Manager, Regional Code Services Portland Cement Association 128 Summerfield Drive, Macon, GA 31210 +1-478-477-5028 [email protected] A paper presented at the April 23-25, 2012 The Infrastructure Security...

Estimation of water soluble hexavalent chromium and total chromium has been devised. For the complete extraction of water soluble hexavalent chromium, leaching period of five days is done. It was ascertained that complete extraction was achieved in five days; the total chromium determination in these samples was done by fusing sample with sodium carbonate up to 1050 C in muffle furnace. Chromiu...

OBJECTIVES Cement contains hexavalent chromium, which is a human carcinogen. However, its effect on cancer seems inconclusive in epidemiologic studies. The aim of this retrospective cohort study was to elucidate the association between dust exposure in the cement industry and cancer occurrence. METHODS The cohorts consisted of male workers in 6 Portland cement factories in Korea. Study subjec...

In this paper, two types of sustainable cementitious composites, geopolymer and magnesium phosphate cement, are introduced. The geopolymer is a type of amorphous alumino-silicate products and magnesium cement is MgO based cementitious material. Geopolymer can be synthesized by polycondensation reaction of geopolymeric precursor, and alkali polysilicates. The MgO cement can be obtained by proper...

MODELING OF HYDRATION KINETICS AND SHRINKAGE OF PORTLAND CEMENT PASTE