An alkali-activated blend of aluminum cement and class F fly ash is an attractive solution for geothermal wells where cement is exposed to significant thermal shocks and aggressive environments. Set-control additives enable the safe cement placement in a well but may compromise its mechanical properties. This work evaluates the effect of a tartaric-acid set retarder on phase composition, micros...

In this paper, the effects of different aluminum to silicon ratios in silicate chains of calcium silicate hydrates (C-S-H) are evaluated on the diffusion coefficient of chloride ions by molecular dynamics method. Tobermorite is a crystalline phase that is used for studying C-S-H properties in nano scale, because of its analogous chemical composition to C-S-H. Aluminum incorporation in C-S-H and...

A basic alumina-spinel low cement castable (LCC) composed of sintered bauxite, reactive alumina, calcined alumina, calcined magnesia, microsilica, and high alumina refractory cement was prepared (castable A) to which 5% sodium hexa-meta phosphate was later added (castable B) to prepare samples for heat treatment at 110ºC, 900ºC, and 1400ºC. Bulk Density (BD), Apparent Porosity (AP), and Cold Cr...

background: an electrocardiogram (ecg) can provide information on subclinical myocardial damage. the presence, and more importantly, the quantity of coronary artery calcification (cac), relates well with the overall severity of the atherosclerotic process. a strong relation has been demonstrated between coronary calcium burden and the incidence of myocardial infarction, a relation independent o...

This study aimed primarily to broaden the limited knowledge presently at hand about ternesite, 5CaO·2SiO2·SO3 (shorthand C5S2S¯,ter), reactivity in calcium sulfoaluminate-calcium aluminate (CSA-CAC) blended cements by exploring hydration of constituents simplified CaO·Al2O3 (CA) + (ter) CaSO4·2H2O (gypsum, gyp) or 12CaO·7Al2O3 (C12A7) (gyp) systems. According earlier research, a mineral constit...

Abstract The construction material from anhydrite-II phosphogypsum is dense in structure and has good water resistance. But its disadvantages are low hydration activity long setting time. In this work, modified by adding a composite activator, which made of sulfuric acid steel slag, β-hemihydrate gypsum calcium aluminate cement. With this, the rate clearly increased time shortened. performance ...