Method for producing a concrete building material, in particular a fibre concrete, particularly preferably an ultra-high-performance fibre concrete, for a construction site, comprising the steps: - Filling a coarse-grain bulk material mixture into a coarse-grain bulk material container; - Filling a fine-grain bulk material mixture into a fine-grain bulk material container, the fine-grain bulk material mixture having a binder; - Processing the coarse-grain bulk material mixture and the fine-grain bulk material mixture with the addition of water into the concrete building material, the coarse-grain bulk material mixture having a proportion of more than 60% by mass of an aggregate having grain sizes of more than substantially 0.04 mm, the fine-grain bulk material mixture having a proportion of more than 60% by mass of a fine-grain mixture having grain sizes of less than substantially 0.2 mm, the fine-grain mixture comprising a rock meal, characterised in that the processing of the coarse-grain bulk material mixture and the fine-grain bulk material mixture with the addition of water into the concrete building material takes place in three successive phases: - the water is first processed with at least one further liquid added, in particular with a liquid liquefier and/or with a nanosilica and/or with a setting accelerator and/or with a setting retarder, to form a liquid mixture; - the fine-grain bulk material mixture is then introduced from the fine-grain bulk material container into the liquid mixture and dispersed to form a suspension; - the coarse-grain bulk material mixture is then added to the suspension from the coarse-grain bulk material container, - the fine-grain bulk material mixture is dispensed from the fine-grain bulk material container to the surface of the liquid mixture, the liquid mixture being in motion in the meantime and/or the coarse-grain bulk material mixture being dispensed from the coarse-grain bulk material container onto the surface of the suspension of the liquid mixture and the fine-grain bulk material mixture, the suspension being in motion in the meantime. - Filling a coarse-grain bulk material mixture into a coarse-grain bulk material container; - Filling a fine-grain bulk material mixture into a fine-grain bulk material container, the fine-grain bulk material mixture having a binder; - Processing the coarse-grain bulk material mixture and the fine-grain bulk material mixture with the addition of water into the concrete building material, the coarse-grain bulk material mixture having a proportion of more than 60% by mass of an aggregate having grain sizes of more than substantially 0.04 mm, the fine-grain bulk material mixture having a proportion of more than 60% by mass of a fine-grain mixture having grain sizes of less than substantially 0.2 mm, the fine-grain mixture comprising a rock meal, characterised in that the processing of the coarse-grain bulk material mixture and the fine-grain bulk material mixture with the addition of water into the concrete building material takes place in three successive phases: - the water is first processed with at least one further liquid added, in particular with a liquid liquefier and/or with a nanosilica and/or with a setting accelerator and/or with a setting retarder, to form a liquid mixture; - the fine-grain bulk material mixture is then introduced from the fine-grain bulk material container into the liquid mixture and dispersed to form a suspension; - the coarse-grain bulk material mixture is then added to the suspension from the coarse-grain bulk material container, - the fine-grain bulk material mixture is dispensed from the fine-grain bulk material container to the surface of the liquid mixture, the liquid mixture being in motion in the meantime and/or the coarse-grain bulk material mixture being dispensed from the coarse-grain bulk material container onto the surface of the suspension of the liquid mixture and the fine-grain bulk material mixture, the suspension being in motion in the meantime.