Disclosed is a method and system for blending a foam modifier with foaming agent online, e.g., as may be particularly useful for gypsum or cement slurries. The foam modifier comprises a fatty alcohol that is added to a gypsum or cement slurry that includes foaming agent, such as an alkyl sulfate surfactant. The fatty alcohol can be a C.sub.6-C.sub.16 fatty alcohol in some embodiments. The use of such a foam modifier can be used, for example, to stabilize the foam, reduce waste of foaming agent, improve void size control in the final product, and improve the gypsum board manufacturing process.

The invention relates to a method for layer-by-layer deposition of concrete, in particular of concrete using a rapidly hydrating cementitious binder.

A first flow and a second flow are supplied to a mixer to obtain extrudable concrete. The pH of the second flow is larger than the pH of the first flow. The first flow comprises a retarded cementitious binder obtainable by mixing a cementitious binder with a retarder comprising boron and sodium. The retarder allows to increase the setting time of the cementitious binder and allows to influence the pH of the first flow in such a way that the pH of the first flow is lower than the pH of a flow equal to the first flow but comprising the cementitious binder instead of the retarded cementitious binder. The second flow comprises a carrier material. The volume fraction of the carrier material is at least 20 vol % of the second flow.

The present invention also relates to a bicomponent cementitious binder composition comprising a first component comprising rapidly hydrating cementitious material.

There is provided an apparatus (100) for manufacturing a cementitious slurry comprising foam, the apparatus (100) comprising: a mixing chamber (101) for mixing a cementitious material and water to form a cementitious slurry, a channel (103) fluidly connected to the mixing chamber (101) at a first end (111), the channel (103) for receiving the cementitious slurry from the mixing chamber (101), the channel (103) extending from the first end (111) and terminating at a second end (112); the channel (103) comprising a foam inlet (106) for introducing foam into the channel (103); wherein the channel (103) comprises a mixing cross section, the mixing cross section comprising a first dimension and a second dimension; the first dimension perpendicular to the second dimension; the first dimension being longer than the second dimension; wherein the foam inlet (106) is configured to introduce foam into the channel (103) in a direction generally parallel to the second dimension. A channel (103) for a cementitious slurry and a method are also provided.

According to the present invention, there is provided an apparatus (100) for manufacturing a cementitious slurry comprising foam, the apparatus comprising: a mixing chamber (101) for mixing a cementitious material and water to form a cementitious slurry, a channel (103) fluidly connected to the mixing chamber (101) at a first end (111), the channel (103) for receiving a cementitious slurry from the mixing chamber (101). In the apparatus (100), the channel (103) extends from the first end (111) and terminates at at least one second end (112). The channel (103) comprises a first foam inlet (106) for introducing foam into the channel (103). The channel (103) further comprises a second foam inlet for introducing foam into the channel (103). The first foam inlet (106) and the second foam inlet are offset along the length of the channel (103). A method using the apparatus (100) is also described.

There is provided an apparatus (100) for manufacturing a cementitious slurry comprising foam, the apparatus (100) comprising: a mixing chamber (101) for mixing a cementitious material and water to form a cementitious slurry, a channel (103) fluidly connected to the mixing chamber (101) at a first end, the channel (103) for receiving the cementitious slurry from the mixing chamber (101), the channel (103) extending from the first end and terminating a second end; the channel (103) comprising a foam inlet (106) for introducing foam into the channel (103); wherein the portion of the channel (103) between the foam inlet (106) and the second end has a length from 400 mm to 1200 mm inclusive, wherein said foam inlet (106) is positioned such that the distance between said first end of said channel (103) and said foam inlet (106) is less than 25% of the distance between said first end of said channel (103) and said second end of said channel (103). A cementitious slurry channel (103) and a method of manufacturing a cementitious slurry are also provided.

Cellular concrete is formed from a cement-based wet mix slurry with a foam entrained into the wet mix. The foam is created using a foaming agent, mixed with water and air using a foam generator. The wet mix is mixed with the foam to form the cellular concrete wet mix. Poor component metering and blending practices in the current state of the art limits the performance capabilities of existing cellular concrete placements. The presently disclosed technology addresses this with a cellular concrete mixing system comprising a dry mix hopper to store a quantity of dry mix, a mixing tank to blend the dry mix and water together to form a wet mix, a holding tank to store a quantity of the wet mix, a foam generator to generate foam from air, water, and foam concentrate, and a blend controller to control operation of the overall mixing system.