The biodeterioration of cementitious materials in sewer networks has become a major economic, ecological, and public health issue. Establishing suitable standardized test is essential if sustainable construction are to be developed qualified for sewerage environments. Since purely chemical tests proven not representative the actual deterioration phenomena real conditions, biological test–named ...

The structural behavior of a chromate aluminate sodalite, Ca8[Al12O24](CrO4)2, at room pressure and on heating from 463 to 982°C was determined by using in situ synchrotron X-ray powder-diffraction data [ = 0.91997(4) Å] and Rietveld refinements. The sample was heated at a rate of about 9.5°C/min., and X-ray traces were collected at intervals of about 17°C. The structure at 463°C is a modulated...

The thermal conductivity of a series of complex aluminates, RE2SrAl2O7, with different rare-earth (RE) ions, has been measured up to 10001C. There is a strong dependence on the atomic number of the RE ion, ranging from an approximately 1/T dependence for the lanthanum strontium aluminate to an almost temperature-independent behavior of the dysprosium strontium aluminate. The latter conductivity...

OBJECTIVE The purpose of this study was to investigate and compare the crystalline structures of recently released MTA Plus (MTA-P), MTA Angelus (MTA-A), DiaRoot BioAggregate (BA) by X-ray diffraction (XRD) analysis. MATERIALS AND METHODS Phase analysis was carried out on powder and set forms of tested materials. The powder specimens placed into sample holders that were packed with a glass sl...

Cementing systems based on calcium aluminate cement (CAC) have been studied as an alternative cement matrix for the encapsulation of intermediate level wastes (ILW) arising from the nuclear industry. CAC-based systems have great potential for the incorporation of aluminium containing ILW owing to the near-neutral internal pH of these binders. However, CAC-based binders usually undergo phase con...

External sulfate attack of concrete is a major problem that can appear in regions where concrete is exposed to soil or water containing sulfates, leading to softening and cracking of the concrete. Therefore, it is important that materials selection and proportioning of concrete in susceptible regions be carefully considered to resist sulfate attack. American Society for Testing Materials (ASTM)...

At present, the most commonly used building material is ordinary Portland cement (OPC). However, OPC has a negative environmental effect during synthesis, with the release of significant amount of CO2 greenhouse gas. The cement industry is responsible for 5-8% of total global anthropogenic CO2 emissions. Geopolymerization is a technology capable of turning industrial wastes into strong and chem...

Mixtures of rare-earth zirconates and aluminates containing Y or + Gd that form a two-phase garnet–fluorite mixture exhibit much slower sintering than pure fluorite at 1400°C. An equivalent Y-free, Gd-containing composition forms perovskite aluminate instead garnet showed faster densification after the metastable decomposes. At 1500°C, Y-free sample also fastest initial rate, whereas there was ...