| 摘要 |
According to the present invention, the reduction of the wettability of porous, lightweight aggregates in mortar mixtures reduces the water absorption of the mortar and in the process the amount m of the aggregate wetted decreases according to the formula (b . F-m)/b . F = 1 + cos alpha -0.166 rho , designated the volume relation of the aggregate. b signifies the particle size and F the surface area of the aggregate, alpha is the wetting angle and rho is the specific weight of the aggregate. From this there emerge consequences for the magnitude of the water/cement ratio which is composed of the following factors: 1. Bulk density a of the aggregate 2. Volume ratio cement to aggregate Vz/Vp 3. The volume ratio, determined by the wettability, of the aggregate, which according to the invention is determined by the formula 1 + cos alpha -0.166 rho . The water/cement ratio is in this case 1/a . (1 + cos alpha -0.166 rho ) . Vz/Vp = f. If the amount m wetted decreases and the wetting angle alpha becomes smaller, the water/cement ratio is higher. On the other hand, the water/cement ratio assumes a smaller value with increase of the wetting angle to 90 DEG , that is to say until complete wettability, because, with the same water addition, a further portion of the water is absorbed by the porous aggregate. The porous aggregates with incomplete wettability, for example perlite, are coated with metal oxides. The process for coating is [lacuna] in ... Original abstract incomplete.
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