CEMENT COMPOSITION FOR SELF-LEVELLING CONCRETE AND SELF-LEVELLING CONCRETE CONTAINING SUCH COMPOSITION

摘要

A cement composition for a self-levelling concrete, includes a mixture of rheology-modifying additives, the combination of at least a first agent for substantially increasing the shear threshold of the concrete in the fluid state, selected from a natural polysaccharide ether, a hydroxyalkyl guar ether, a hydroxyethylcellulose or a hydroxypropyl guar, which are hydrophobically modified with the introduction of hydrophobic side grafts, and at least a second viscosity-increasing agent for substantially increasing the viscosity of the concrete in the fluid state, selected from a non-hydrophobically-modified hydroxyalkylcellulose having a degree of polymerization between approximately 500 and approximately 4500 and a viscosity of less than 50 PA·s in aqueous solution at 2 wt.-% and a poly (ethylene oxide), in order to limit or prevent the dynamic segregation of granulates in the concrete during the implementation thereof. The use of such a composition can replace the presence of a filler in the concrete, in particular a self-levelling concrete, without diminishing the performance concerning the spreading thereof, the sieve stability, the bleeding and the dynamic segregation relative to a concrete containing a filler, in particular a concrete having the same water/cement ratio.