Experimental Study on Pore Characteristics and Fractal Dimension Calculation of Pore Structure of Aerated Concrete Block

Jun Fu,Yue Yu

doi:10.1155/2019/8043248

Abstract

It is important to control and predict the macroscopic properties through pore structure parameters of cement-based materials. Microscopic pore structure of concrete has many characteristics, such as sizes and disordered distribution. It is necessary to use fractal theory to describe the pore structure of concrete. In order to establish the relationship between the pore structure characteristics of aerated concrete and porosity, shape factor, pore superficial area, average pore diameter, and average diameter, the fractal dimension of the pore structure was used to evaluate the pore structure characteristics of aerated concrete. The X-ray computed tomography (CT) images of the aerated concrete block pore structure were obtained by using the XTH320 series X-ray three-dimensional microscope. The pore characteristics of aerated concrete block were studied according to Image-Pro Plus (IPP). Based on the research of the fractal dimension measurement methods, the proposed MATLAB program automatically determined the fractal dimension of the aerated concrete block pore structure images. The research results indicated that the small pores (20 μm∼60 μm) of aerated concrete block account for a large percentage compared with the large pores (60 μm∼400 μm or more) from pore diameter distribution and the pore structure of aerated concrete block has obvious fractal features and the fractal dimension of aerated concrete block pore structure images were calculated to be in the range of 1.775–1.805. The pore fractal dimension has a strong correlation with the pore fractal characteristics of aerated concrete blocks. The fractal dimension of the pore structure linearly increases with porosity, shape factor, and pore surface area. The fractal dimension of the pore structure decreases with the average pore size and average diameter. Thus, the fractal dimension of the pore structure that is calculated by the MATLAB program based on fractal theory can be assumed as the integrative evaluation index for evaluating the pore structure characteristic of aerated concrete block.

Highlights

With the continuous promotion of energy conservation and emission reduction policies, the aerated concrete blocks are widely used in building engineering, due to their low density, thermal insulation property, sound insulation property, antiseismic property, and easy processing
In order to study the pore structure of aerated concrete block, fractal theory was introduced into the study
Jin et al [33] obtained the relationships between the pore surface fractal dimension and the pore characteristic parameters of cement mortar based on the mercury intrusion porosimetry (MIP) method and fractal model. e pore structure parameters of concrete represent the complexity of pore structure

Summary

Introduction

With the continuous promotion of energy conservation and emission reduction policies, the aerated concrete blocks are widely used in building engineering, due to their low density, thermal insulation property, sound insulation property, antiseismic property, and easy processing. Us, it is necessary to study the pore structure parameters in order to adjust macroscopic properties of aerated concrete. Jin et al [33] obtained the relationships between the pore surface fractal dimension and the pore characteristic parameters of cement mortar based on the MIP method and fractal model. E aerated concrete block CT slice images contain lots of pore structure information compared with the data measured based on the MIP method. Us, MATLAB is used to process aerated concrete block pore structure slice images in this study. E relationships between the fractal dimension of the pore structure and the pore characteristic parameters are studied based on the program calculation in this study, which is used to establish the relationships between the pore characteristic parameters and the macroscopic properties of the aerated concrete blocks E pore structure of aerated concrete block will not be damaged and be preserved completely by X-ray computed tomography (CT). e aerated concrete block CT slice images contain lots of pore structure information compared with the data measured based on the MIP method. us, MATLAB is used to process aerated concrete block pore structure slice images in this study. e Fraclab program was introduced to calculate the fractal dimension of pore structure images. e program-calculated value is compared to the theoretical value by the fractal dimension of the fractal images. e relationships between the fractal dimension of the pore structure and the pore characteristic parameters are studied based on the program calculation in this study, which is used to establish the relationships between the pore characteristic parameters and the macroscopic properties of the aerated concrete blocks

Experimental

Methods

Experimental Results and Discussion