纳米碳酸钙和SBS复合改性沥青的性能

Performance of nano-calcium carbonate and SBS compound modified asphalt

用直接剪切的方法制备纳米碳酸钙和SBS复合改性沥青,对纳米碳酸钙和SBS复合改性沥青的常规技术性能、SHRP技术性能及动态力学性能等进行试验研究。研究结果表明,在SBS改性沥青(SBS含量为5%)中掺入纳米碳酸钙后,随着纳米碳酸钙含量的增加,复合改性沥青的软化点、针入度指数提高,但5℃时延度降低;纳米碳酸钙和SBS含量均为5%的复合改性沥青满足PG 76—22的指标要求;纳米碳酸钙和SBS复合改性沥青的贮能模量E′、损耗模量E″在试验温度区间(-30～30℃)均比SBS改性沥青的高,但复合改性沥青的损耗角正切(tanδ)在10℃以下略比SBS改性沥青的高,而在10℃以上则略比SBS改性沥青的低,说明在SBS改性沥青中掺入纳米碳酸钙获得了良好的增强效果,且低温下的韧性有所提高。

Nano calcium carbonate and SBS complex-modified asphalt were prepared by direct shear. Their common technical performance, SHRP technical performance and dynamic mechanical property were tested. The results show that both the softening point and penetration index are heightened with the increase of nano calcium carbonate, but the ductility at 5 ℃ reduces when the SBS modified asphalt （the mass fraction of SBS is 5%） is mixed with nano calcium carbonate. The modified asphalt satisfies the specification requirements of PG 76-22 when the content of nano calcium carbonate and SBS are all 5%. Storage modulus E′ and loss modulus E″ of the nano calcium carbonate and SBS compound modified asphalt are a little higher than those of the SBS modified asphalt in the test temperature range （-30-30 ℃）. However, the loss tangent （tan δ） of compound modified asphalt is a little higher than that of SBS modified asphalt at 10 ℃, while the nano calcium carbonate and SBS compound modified asphalt is a little lower than that of SBS modified asphalt above the temperature of 10 ℃. This suggests that the nano calcium carbonate can enhance SBS modified asphalt as well as improve low temperature toughness.