一种能缩短张拉龄期的复合掺合料高性能混凝土试验研究

摘要

CCM复合掺合料的主要成份是磨细的纳米级的超细岩石颗粒，以及掺加少部分的活性掺合料，特性是低活性、超细，它在混凝土中的主要作用机理是物理方法填充混凝土浆体内部孔隙，提高混凝土密实度，它可以减薄拌合物骨料周围的润滑层，并生成更加密实的微结构。通过掺加水泥用量15％、20％的CCM复合掺合料配制高性能混凝土来进行试验研究，结果表明，掺加CCM复合掺合料后混凝土强度发展对温度不敏感，混凝土水化温度降低。通过在京沪高速铁路悬灌梁中应用，证明20％掺量的CCM复合掺合料高性能混凝土能够提高3d龄期的弹性模量和抗压强度，缩短张拉龄期，应用效果较好。%CCM composite admixture is mainly composed of fine-grained nano-sized superfine rock particles and is mixed with few active admixtures and has low-activity and superfine character.Its main mechanism is to fill the internal pore of concrete slurry with physical method so as to improve the compactness of concrete.The lubrication layer can be made thinaer around aggregate mixture and denser microstructure is generated.An experimental study is made on high per-formance concrete with CCMcomposite mineral admixtures respectively adding cement content of 15%and 20%,the re-sult shows the strength development of concrete with CCM composite admixture is not sensitive to temperature and the hy-dration temperature of concrete decreases.The application in cantilever beam on Beijing-Shanghai high-speed railway has proved CCM composite admixture with cement content of 20%for high performance concrete can improve the modu-lus of elasticity and compressive strength for 3 days and shorten the tension time.It has good application effect.