硅酸盐水泥的细度对其水化过程和力学性能的影响

Effect of fineness of Portland cement on hydration process and mechanical properties

细度高低会影响硅酸盐水泥的水化特性和力学性能,从而影响混凝土的力学性能、工作性和耐久性。本文研究了组成相同、细度不同的水泥的水化特性和力学性能发展,期望对于新的水泥标准确定合适的细度范围提供依据。研究发现,以现在一般商业化生产的水泥的细度为基准,比表面积小于此范围的较粗的水泥早期水化程度低,强度低;但水化反应持续时间较长,后期强度增长率大。比表面积大于此范围的较细的水泥早期水化程度高,强度高;但水化反应持续时间较短,后期强度增长率小。水化90 d以后,不同细度的水泥的水化程度和强度基本相当。兼顾水泥的早期和后期性能,现行标准规定的水泥细度范围(比表面积在350~380 m^(2)/kg之间)是适宜的。

The fineness of Portland cement can influence its hydration process and mechanical properties,as well as the workability,mechanical property and durability of concrete.The hydration characteristics and strength development of Portland cement with same composition but different fineness were studied.The results is expect to be a basis provided to the revision of national standard to determine the suitable fineness range of cement.The results show that using the fineness of commercial cement as a benchmark,the coarse cement with low specific surface area gains low hydration degree and low strength in early age.Its hydration goes continuously in long period to get a high strength increasing rate in later age.The fine cement with high specific surface area gains high hydration degree and high strength in early age.Its hydration rate declines quickly to get a low strength increasing rate in later age.The hydration degree and strength of cements with different fineness is almost same after 90 d hydration age.The fineness range(specific surface area between 350~380 m^(2)/kg)of cement specified by active standard is appropriate balancing the early and later properties of cement.