| 摘要 |
<p>Roads, embankments or foundations are made using a filler, gypsum residue obtd. from the mfr. of phosphoric acid, the gypsum possessing a moisture content of 8-23%, and CBR 25-32 for a compaction near to the normal Proctor value. The gypsum is pref. neutralised by an alkali (ne earth) salt or hydroxide, esp. Ca(OH)2, and neutralisation may be undertaken (a) in a continuous manner at the plant mfg. the H3PO4; (b) ont he road construction site by mixing with the neutralisation agent before the gypsum is used; or (c) using alternate layers of gypsum and the neutralisation agent when making the filler substructure. The gypsum may also be mixed with other conventional fillers. Prod. may be used e.g. for roads for motor vehicles or parking zones. Waste gypsum, CaSO4, 2H2 is available in large amts. from H3PO4 mfr. and its disposal presents ecological problems. Due to the CBR value at the stated moisture content, the gypsum can be used directly without being mixed with or adding water.</p> |
