CEMENT

[:ru]Али М. М.[:en]Ali, M. M.[:] [:ru]Национальный совет по цементам и строительным материалам, Баллабгар, Харьяна, Индия[:en]National Council for Cement and Building Materials, Ballabgarh, Haryana, India[:]

[:ru]Сатиш К. Агарвал[:en]Agarwal, S. K.[:] [:ru]Национальный совет по цементным и строительным материалам, Харьяна, Индия[:en]National Council for Cement and Building Materials, Haryana, India[:]

Alitinform №2 (19) 2011 г. 44-49 стр.

Abstract

ranulated blast furnace slag on hydration in presence of alkali ions activators results in formation of low basic calcium silicate hydrates with CaO/SiO₂ ratio less than one. The formation of poorly crystalline alkaline-alkali earth compounds of low solubility with fixation of large amount of alkali ions in the hydrate phases shows rapid hardening and high early strength developments. The effect of such slag cement on reactive siliceous aggregates is found to be very poor as compared to ordinary Portland cement (OPC).

Mortar-bar tests conducted on such cementitious compositions prepared using granulated slag and caustic alkali (4.0–6.4 % Na₂O equivalent) and reactive aggregates such as strained quartz and Pyrex glass showed linear change of –0.028 and –0.019 % respectively when cured at temperature of 38 and 60 °C for the period of 30 and 14 days. However, in case of OPC containing 1.0 % Na₂O equivalent, the mortar bar linear change observed with Pyrex glass on curing for 14 days was much higher, i.e. +0.10 % respectively. The compressive strengths for these typical alkaline cements at 28 days were found to be in the range of 50–70 N/mm².

Key words:

щелочь; цемент; некристаллический; шлак; цеолит