IMPROVING THE ROBUSTNESS OF FRESH SELF-COMPACTING CONCRETE USING SMALL QUANTITIES OF FINE ADDITIONS

Although the use of self-compacting concrete has many advantages compared to vibrated concrete, its application in Europe is mainly limited to the precast industry. The onsite use of self-compacting concrete is hampered by a higher material cost, higher formwork pressures, and a reputation for 'unpredictability': self-compacting concrete has a higher sensitivity to small deviations in the properties and proportions of its ingredients. This paper describes the experimental results of an attempt to improve the robustness of fresh self-compacting concrete equivalent mortars by adding small amounts of purified clays, welan gum, diutan gum, fly ash, silica fume, ground granulated blast furnace slag, and a natural clinoptilolite type zeolite. Small additions of diutan gum, welan gum, and ground granulated blast furnace slag caused an increase of the robustness of fresh self-compacting concrete, and all small additions of the other materials induced a decrease of the robustness.