| 摘要 |
<p>PURPOSE: To reutilize a large amt. of spent concrete and to reduce its volume by sintering a fine powder obtained by crushing and screening the spent concrete to produce an aggregate. CONSTITUTION: Spent concrete is crushed and then screened, the grains having >=5mm diameter are utilized as a coarse aggregate material and the grains having 0.3-5mm diameter as a thin aggregate, and the grains having <=0.3mm diameter are recovered as a fine powder. The fine powder is granulated or formed into a string, then at least one king among SiO2 , CaO, Al2 O3 , Fe2 O3 and R2 O (R is an alkali metal) is added to the product at need, the mixture is sintered at 1200-1600 deg.C for 0.3 to 3hrs and screened at need, to obtain a coarse aggregate and/or a thin aggregate.</p> |
