基于纳米压痕技术的蒸养高强水泥浆体微观力学性能试验研究

Experimental study on micromechanical properties of steam-cured high strength paste based on nanoindentation techniques

为从微观尺度上理解铁路预制构件蒸养混凝土力学特性,论文采用纳米压痕试验及其统计分析技术,以铁路预制构件常用的C60混凝土为基础,研究了相同水灰比蒸养高强水泥浆体主要水化物相的力学性能,比较分析了蒸养和标养条件对浆体各物相的力学性能的影响。研究表明,养护条件对水泥浆体中各主要水化物相的力学性能及体积含量有较大影响;相较于标养条件,蒸养条件下高强水泥浆体的低密度和高密度CSH凝胶的压痕模量稍大,且高密度CSH凝胶数量明显增多,而Ca(OH)2晶体的压痕模量则偏低。

For the sake of further understanding the mechanical behavior of steam-cured concrete applied in railway precast from micro- scale view, the present paper investigates the micromechanical properties of main hydration products of steam-cured high strength paste with water to binder ratio similar to C60 concrete usually used in railway precast by utilization of nanoindentation techniques. The effects of curing conditions such as steam curing and standard curing on mechanical properties of high strength paste are comparatively discussed. The results indicate that the mechanical properties of main hydration products of high strength paste and its volume content are remarkably influenced by curing conditions. Compared to the standard curing, the indentation modulus of low density CSH and high density CSH of steam-cured high strength paste is slightly larger, and the volume content of high density CSH is obviously higher. However, the indentation modulus of Ca（OH）2 crystal is lower.