Destruction of cement stone modified with a plasticizer and a nanoscale aluminum oxide

Abstract

It is well known that hydration and hardening of Portland cement are associated with complicated physical and chemical processes, in particular the interaction of clinker minerals with water to form new hydrate phases of different composition. Sometimes the presence of various substances can affect these processes leading to self-destruction of the hydrated cement stone. The morphology and composition of damaged cement stone modified with an additive and with a nanoscale aluminum oxide were studied. It is shown that in the presence of the 'Linamix PC' plasticizer and a nanoscale aluminum oxide, well-crystallized Ca(OH)2 plates with an average thickness of 1.5 microns and a length and width equal to 300-400 microns are formed. Also, a network of thread-like ettringite with a diameter of less than 1 micron on the surface of microcracks of cement stone is formed. Most likely the cement stone sample could be damaged by the forces of crystallization pressure during the growth of both Ca(OH)2 and ettringite crystals. © Published under licence by IOP Publishing Ltd.