Case study of the gradient features of in situ concrete

Case Studies in Construction Materials

Pengkun Hou¹  Rui Zhang¹  Xin Cheng¹ 

[1] School of Materials Science & Engineering, University of Jinan, Jinan 250022, Shandong, China;

关键词: Concrete;    Gradient;    Carbonation;    Pore;    Calcium-leaching;    Micro-indentation;   

DOI  :  10.1016/j.cscm.2014.08.003

来源: DOAJ

【 摘 要 】

The recognition of gradient features of the properties of in situ concrete is important for the interpretation/prediction of service life. In this work, the gradient features: water absorption, porosity, mineralogy, morphology and micromechanical properties were studied on two in situ road concretes (15 and 5 years old, respectively) by weighing, MIP, XRD, IR, SEM/EDS and micro-indentation techniques. Results showed that a coarsening trend of the pores of the concrete leads to a gradual increase of liquid transport property from inside to outside. Although the carbonation of the exposed surface results in a compact microstructure of the paste, its combined action with calcium-leaching leads to a comparable porosity of different concrete layers. Moreover, the combining factors result in three morphological features, i.e. a porous and granular exposed-layer, a fibrous and porous subexposed-layer and a compact inner-layer. Micro-indentation test results showed that a hard layer that moves inward with aging exists due to the alterations of the mineralogy, the pore and the gel structure.

【 授权许可】

Unknown