There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Changes in portlandite morphology with solvent composition: Atomistic simulations and experiment

Supplementary cementitious materials

The calcium silicate hydrates

https://www.tpbin.com/Uploads/Subjects/0c9c42eb-ff6e-4ada-b126-dbb3146ed30e.pdf

Comparison of methods for arresting hydration of cement

The influence of water removal techniques on the composition and microstructure of hardened cement pastes

Radioactive waste streams that include metallic uranium are incompatible with conventional ordinary Portland cement (OPC)-based encapsulation matrices. These encapsulation systems are essentially composite materials that incorporate high replacement levels of pulverised fly ash (PFA) or blast furnace slag (BFS). A potential alternative encapsulant for the treatment of problematic waste streams is magnesium phosphate cement. This paper discusses the fundamental characterisation results obtained from two magnesium phosphate cement formulations being developed in the UK for the encapsulation of metallic intermediate level waste (ILW). When compared to conventional OPC based systems, the two magnesium phosphate cement formulations investigated have lower pH, are able to chemically combine more mix water into the system and provide sufficient workability at water/solid ratios close to the theoretical confines needed for paste saturation. The results presented have confirmed compliance of this material...

Development of magnesium phosphate cements for encapsulation of radioactive waste

Legacy radioactive wastes arising from reprocessing of nuclear fuels in the UK are classified as intermediate level waste (ILW), which contain things such as aluminium and magnesium. Blast furnace slag (BFS) composite cements are used to encapsulate ILW. These cements have a high pH which is advantageous to limit the mobility of some of the radioactive species but can cause corrosion of metals. The present paper describes some fundamental aspects of corrosion of aluminium and magnesium in BFS composite cements.The corrosion of aluminium produced an interface between aluminium and cement which was porous with a series of zones containing bayerite (Al(OH)3) and stratlingite (2CaO.Al2O3.SiO2.8H2O). With magnesium, the main corrosion product was found to be brucite (Mg(OH)2) and the porous zone was less pronounced. The hydration of the bulk cement did not appear to be affected by the corrosion of these metals.

Corrosion of aluminium and magnesium in BFS composite cements

The disposal of radioactive ferric floc.

Isothermal conduction calorimetry has been used to monitor the early hydration of Portland–blastfurnace slag (BFS)-blended cements. Portland:BFS composite cements with ordinary Portland cement replacements from 0 to 90 wt% were studied at curing temperatures from 12° to 90°C. Peak II, principally associated with alite (Ca3SiO5) hydration, was accelerated with increasing temperature for all blends. Peak S, associated with BFS hydration, was particularly noticeable at 40° and 60°C. At higher curing temperatures, peak S merged with peak II, indicating thermal activation of BFS. Novel plots of total heat output against percentage replacement show that BFS contributes to the heat of hydration, even at temperatures below its thermal activation.

J. Hill

Papers

The influence of water removal techniques on the composition and microstructure of hardened cement pastes

Development of magnesium phosphate cements for encapsulation of radioactive waste

Corrosion of aluminium and magnesium in BFS composite cements

The disposal of radioactive ferric floc.

Effect of Temperatures up to 90°C on the Early Hydration of Portland–Blastfurnace Slag Cements