![]() ![]() Preferably the range of welan gum is 0.1-0.5%.īy cement compositions is meant hydraulic cements, i.e., finely ground and calcined calcium silicates and calcium aluminates which when mixed with water react to form a hard, rock-like mass. Furthermore, these improvements are retained at elevated temperatures (i.e., greater than 93° C.). It has now been found that cement compositions comprising 0.01 to 0.9% welan gum by weight of dry cement exhibit improved workability, suspension of aggregates, air entrainment, sag resistance, flow characteristics, and resistance to water loss. Fumed silica is used as an additive to make stronger concrete with reduced permeability. Other polymers, such as the polyvinyl alcohols and methyl methacrylates, have been used to reduce friction when pumping these pastes and to otherwise modify their workability. Bentonite clay has been used for this purpose. Cellulosic polymers have been used in cements to control sedimentation of particles in the pastes. Freezing point depressants are used when cements are to be poured in subfreezing temperatures. Thus, long fibers such as asbestos reduce the sagging of these pastes and thus is beneficial when applying tiles to a vertical surface. Various additives have been used in these cement compositions to modify their properties for specialized applications. When water is added to the cement, this forms a paste which then hardens to a solid structure. ![]() A process of claim 9 wherein the slurry further comprises 0.1 to 1.5% dispersant, based on the weight of the dry cement.Ĭoncretes and mortars are cement compositions additionally containing aggregate (e.g., sand and rock) and water. A process for improving the suspension of cement slurries according to claim 7 which comprises incorporating into said slurries 0.1-0.5% welan gum, based on the weight of the dry cement.ġ0. A process of claim 7 wherein the slurry further comprises 0.1 to 1.5% dispersant, based on the weight of the dry cement.ĩ. A process for improving the suspension of cement slurries which comprises incorporating into said slurries 0.01-0.9% welan gum, based on the weight of the dry cement.Ĩ. A process for controlling water loss from cement slurries according to claim 5 which comprises incorporating into said slurries 0.1-0.5% welan gum, based on the weight of the dry cement.ħ. ![]() A process for controlling water loss from cement slurries which comprises incorporating into said slurries 0.01-0.9% welan gum, based on the weight of the dry cement.Ħ. A cement composition of claim 1, further comprising 0.1 to 1.5% dispersant, based on the weight of the dry cement.ĥ. A cement composition of claim 1 wherein the welan gum 5% viscosity ranges from 10,000 cP to about 100 cP is measured at 60 rpm, on an LVT Brookfield viscometer, spindles 4 and 2 respectively, at about 20-25° C.Ĥ. A cement of claim 1 comprising 0.1-0.5% welan gum.ģ. ![]() A hydraulic cement composition comprising dry cement and 0.01-0.9% (wt) welan gum, based on the weight of the dry cement, whereby a cement slurry made therefrom is an improved suspension.Ģ. ![]()
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