| 摘要 |
<p>Asphalt flooring contg. embedded pipes for liq-or steam heating, comprises 20-40 esp. 27 wt.% gravel, 10-30 esp. 25 wt.% natural crushed sand, 10-30 esp 11 wt.% washed natural sand, 20-35 esp 29 wt.% stone flour and 7-10 esp 8 wt.% bitumen. The bitumen contains 1.5-4.5 esp 2.2 wt.% copolymer esp EVA or styrene-butadiene copolymer. The compsn. has high thermal stability, good sheological properties and flexibility even at high heating temp. The compsn. does not attack metal pipes and has a similar expansion coeff to plastic pipes so that there is no abrasion of the pipes due to temp fluctuations. The compsn showed practically no change in sheological properties at -30 to 60 deg.C. Cracks formed at -35 deg.C.</p> |
