Building material and method for manufacturing building material

A building material having a convex part formed on a front surface thereof, the convex part including a first lateral surface part and a second lateral surface part corresponding to the first lateral surface part, wherein

• the building material is formed from a mixture containing a hydraulic material, an admixture, and a plant-based reinforcing material, to which the hydraulic material and the admixture are attached,
• the mixture contains about 30% by mass of the hydraulic material, about 40% by mass of the admixture, and about 30% by mass of the plant-based reinforcing material,
• at least in the convex part, the plant-based reinforcing material is distributed in the mixture and the hydraulic material and the admixture are attached to the plant-based reinforcing material,
• a distribution of the plant-based reinforcing material in the first lateral surface part and a distribution of the plant-based reinforcing material in the second lateral surface part are substantially the same, and
• the building material has a front surface layer having the convex part, a first core layer disposed on the front surface layer, a second core layer disposed on the first core layer, and a back surface layer disposed on the second core layer, and the first core layer is formed of powder having smaller sizes than the powder forming the second core layer, wherein
• the building material is formed by I) supplying the mixture to a first sifting machine including a first meshed sieve sheet at an upper stream portion from a first raw-material supplying part and a downstream potion from a second raw-material supplying part, II) repeatedly pulling and bending the first meshed sieve sheet, causing the first meshed sieve sheet to vibrate vertically and the mixture to fall, due to its own weight and without receiving artificial side wind, into a template having a concaved portion, which travels continuously at a constant speed and in a constant direction under the first sifting machine, so that i) the mixture accumulates over an entire surface of the template in substantially the same ratio and in substantially the same amount, the concaved portion of the template corresponding to the convex part of the building material, and ii) the front surface layer and the first core layer disposed on the front surface layer are formed from the mixture, the mixture formed from loosened powder raw materials fallen due to their own weight and without receiving artificial side wind, and further III) supplying the mixture to a second sifting machine including a second meshed sieve sheet at an upper stream portion of the second sifting machine from a third raw-material supplying part, and IV) repeatedly pulling and bending the second meshed sieve sheet, causing the second meshed sieve sheet to vibrate vertically and the mixture to fall, due to its own weight and without receiving artificial side wind, into the template, which travels continuously at the constant speed and in the constant direction under the second sifting machine, so that i) the mixture accumulates over the entire surface of the template in substantially the same ratio and in substantially the same amount, and ii) the second core layer disposed on the first surface layer and the back surface layer disposed on the second core layer are formed from the mixture, the mixture formed from loosened powder raw materials fallen due to their own weight and without receiving artificial side wind,
• the first sifting machine is arranged to be inclined along the constant direction in which the template travels so that the upper stream portion is higher than the downstream potion of the first sifting machine,
• the second sifting machine is arranged to be inclined along the constant direction in which the template travels so that the upper stream portion, to which the mixture is added, is higher than a downstream potion of the second sifting machine,
• the convex part includes a first edge part that is an edge part of the first lateral surface part and a second edge part that is an edge part of the second lateral surface part and that corresponds to the first edge part, and
• a distribution of holes formed in the first edge part and a distribution of holes formed in the second edge part are substantially the same.