STATEMENT OF PROBLEM Resinous die materials have several important advantages including strength, abrasion resistance, and detail reproduction. Despite these advantages, the shrinkage of resinous die materials during polymerization has limited their widespread acceptance. PURPOSE This study determined whether a retarded setting reaction could improve the accuracy of an epoxy resin die system,...

The basis for some common gypsum wallboard mold remediation practices was examined. The bottom inch of several gypsum wallboard panels was immersed in bottled drinking water; some panels were coated and others were untreated. The panels were examined and tested for a period of 8 weeks. This study investigated: (a) whether mold growth, detectable visually or with tape lift samples, occurs within...

A considerable amount of Hg is retained in flue gas desulfurization (FGD) gypsum from Wet Flue Gas Desulfurization (WFGD) systems. For this reason, it is important to determine the species of Hg in FGD gypsum not only to understand the mechanism of Hg removal by WFGD systems but also to determine the final fate of Hg when FGD gypsum is disposed. In this study, Temperature Programmed Decompositi...

The CEMHYD3D model has been extended at the University of Twente in the last ten years [1,2]. At present the cement hydration model is extended for the use of gypsum. Although gypsum was present in the model already, the model was not suitable for high contents of gypsum and did not include the transitions between the different calcium sulphate phases (anhydrite, hemihydrate and gypsum). Beside...

The CEMHYD3D model has been extended at the University of Twente in last ten years. At present the cement hydration model is extended for the use of gypsum. Although gypsum was present in the model already, the model was not suitable for high contents of gypsum and did not include the transitions between the different calcium sulphate phases (anhydrite, hemihydrate and gypsum). Besides that gyp...

This research determines which of the phenomena that appear during cavitation are responsible for the erosion of some brittle water soluble materials, such as gypsum and alum, when exposed to a high intensity ultrasound field over the cavitation level. The observation that gypsum suffers no erosion under the effect of an ultrasound field when the material is irradiated in a saturated solution o...

The orientation of steel fibers in magnetically driven concrete and magnetically driven mortar was experimentally studied in this paper using a magnetic method. In the magnetically driven concrete, a steel slag was used to replace the coarse aggregate. In the magnetically driven mortar, steel slag and iron sand were used to replace the fine aggregate. A device was established to provide the mag...

The effects of aggregate characteristics on flow ability of mortar mixtures were investigated. Two types, five single sizes, and three gradations of fine aggregate were considered. Uncompacted voids of the aggregates were measured. Flow properties of 166 mortar batches made with the aggregates, together with different sand-to-cement ratios (s/c) and water-to-cement ratios (w/c), were evaluated ...

As one of the important factors affecting structural durability cementitious materials, sulphate erosion not only reduces service life material but also poses a threat to safety project. At present, scholars around world have conducted extensive research on topics related external attacks and achieved fruitful results. However, process mechanism attack degradation gelling are clear. In this pap...

Concrete surface resistivity can be measured non-destructively, providing an indirect measurement of microstructural development which related to strength development. However, relating and challenging for limestone calcined clay cements (LC3) since they contain mineral components varying composition reactivity. In this study LC3 formulations, concrete until 56 days hydration mortar compressive...