Study on effect of mechanical sand on mechanical properties and fractal characteristics of mortar pore structure

This study investigated the pore structure and its effects on mechanical properties of lightweight cellular concrete (LCC) in order to understand more and detailed characteristics of such structure. As part of investigation, environment scanning electron microscopes (ESEM) and industrial high-definition (HD) macro photography camera were separately used to capture and compare images of specimens. Physical properties of the pore structure, including pore area, size, perimeter, fit ellipse, and shape descriptors, were studied based on the image processing technology and software applications. Specimens with three different densities (400, 475, and 600 kg/m3) were prepared in the laboratory. Firstly, the effects of density on the characteristics of pore structure were investigated; furthermore, mechanical properties (compressive strength, modulus of elasticity and Poisson’s ratio, flexural strength and splitting tensile strength of LCC) were tested. The relationships among pore characteristics, density, and mechanical properties were analyzed. Based on the results obtained from the lab test—comparisons made between specimens with high-densities and those with low-densities—it was found significant variability in bubble size, thickness, and irregularity of pores. Furthermore, the increase of density is accompanied by better mechanical properties, and the main influencing factors are the thickness of the solid part and the shape of the bubble. The thicker of solid part and more regular pores of LCC has, the better mechanical properties are.

Download Full-text

The characterization and preparation of porous low dielectric films using various cyclodextrins as template materials

MRS Proceedings ◽

10.1557/proc-766-e8.10 ◽

2003 ◽

Vol 766 ◽

Cited By ~ 7

Author(s):

Jin-Heong Yim ◽

Jung-Bae Kim ◽

Hyun-Dam Jeong ◽

Yi-Yeoul Lyu ◽

Sang Kook Mah ◽

...

Keyword(s):

Thin Film ◽

Mechanical Properties ◽

Dielectric Constant ◽

Pore Structure ◽

Pore Diameter ◽

Dielectric Films ◽

Low Dielectric Constant ◽

Cyclodextrin Derivatives ◽

Low Dielectric ◽

Low K

AbstractPorous low dielectric films containing nano pores (∼20Å) with low dielectric constant (<2.2), have been prepared by using various kinds of cyclodextrin derivatives as porogenic materials. The pore structure such as pore size and interconnectivity can be controlled by changing functional groups of the cyclodextrin derivatives. We found that mechanical properties of porous low-k thin film prepared with mCSSQ (modified cyclic silsesquioxane) precursor and cyclodextrin derivatives were correlated with the pore interconnection length. The longer the interconnection length of nanopores in the thin film, the worse the mechanical properties of the thin film (such as hardness and modulus) even though the pore diameter of the films were microporous (∼2nm).

Download Full-text

Effects of graphene oxide on pore structure and mechanical properties of cementitious composites

Composite Structures ◽

10.1016/j.compstruct.2019.111709 ◽

2020 ◽

Vol 234 ◽

pp. 111709 ◽

Cited By ~ 3

Author(s):

Su-Jin Lee ◽

Seong-Hoon Jeong ◽

Dong-Uk Kim ◽

Jong-Pil Won

Keyword(s):

Mechanical Properties ◽

Graphene Oxide ◽

Pore Structure ◽

Cementitious Composites

Download Full-text

Preparation Techniques and Property Evaluations of Highly Air Permeable Needle-Punched Geotextiles

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.749.278 ◽

2015 ◽

Vol 749 ◽

pp. 278-281

Author(s):

Jia Horng Lin ◽

Jing Chzi Hsieh ◽

Jin Mao Chen ◽

Wen Hao Hsing ◽

Hsueh Jen Tan ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Service Life ◽

Mechanical Strength ◽

Pore Structure ◽

Test Results ◽

Needle Punching ◽

Pet Fibers ◽

Environmental Requirements ◽

Preparation Techniques

Geotextiles are made of polymers, and their conjunction with different processes and materials can provide geotextiles with desirable characteristics and functions, such as filtration, separation, and drainage, and thereby meets the environmental requirements. Chemical resistant and mechanical strong polymers, including polyester (PET) and polypropylene (PP), are thus used to prolong the service life of the products made by such materials. This study proposes highly air permeable geotextiles that are made with different thicknesses and various needle punching speeds, and the influences of these two variables over the pore structure and mechanical properties are then examined. PET fibers, PP fibers, and recycled Kevlar fibers are blended, followed by being needle punched with differing spaces and speeds to form geotextiles with various thicknesses and porosities. The textiles are then evaluated for their mechanical strength and porosity. The test results show that a thickness of 4.5 cm and 1.5 cm demonstrate an influence on the tensile strength of the geotextiles, which is ascribed to the webs that are incompletely needle punched. However, the excessive needle punching speed corresponding to a thickness of 0.2 cm results in a decrease in tensile strength, but there is also an increase in the porosity of the geotextiles.

Download Full-text

Experiment Study on Mechanics and Pore Structure of Steel Fibre Reinforced Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.150-151.825 ◽

2010 ◽

Vol 150-151 ◽

pp. 825-828

Author(s):

Yan Wang ◽

Di Tao Niu ◽

Yuan Yao Miao ◽

Nai Qi Jiao

Keyword(s):

Mechanical Properties ◽

Experimental Study ◽

Reinforced Concrete ◽

Pore Structure ◽

Steel Fibre ◽

Fibre Reinforced Concrete ◽

Experiment Study ◽

Steel Fibre Reinforced Concrete ◽

Mercury Intrusion ◽

Strength And Durability

The concrete microstructure can affect its macroscopic properties, such as the strength and durability, etc. Based on the experimental study of cube compressive strength of steel fibre reinforced concrete, splitting tensile strength, flexural strength, and using by mercury intrusion method to test the pore structure of steel fibrous, this paper analyzes the influence of fibre on concrete pore structure. And then on mechanical properties of concrete from microcosmic perspective.

Download Full-text

Effects of Nano-CaCO3/Limestone Composite Particles on the Hydration Products and Pore Structure of Cementitious Materials

Advances in Materials Science and Engineering ◽

10.1155/2018/5732352 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 8

Author(s):

Huashan Yang ◽

Yujun Che

Keyword(s):

Mechanical Properties ◽

Pore Structure ◽

Reaction System ◽

Cementitious Materials ◽

Limestone Powder ◽

Composite Particles ◽

Gravimetric Analysis ◽

Hydration Products ◽

Scanning Calorimetry ◽

Necked Flask

The agglomeration of nano-CaCO3 (NC) is the largest bottleneck in applications in cementitious materials. If nano-CaCO3 modifies the surface of micron-scale limestone powder (LS), then it will form nano-CaCO3/limestone composite particles (NC/LS). It is known that micron-scale limestone is easily dispersed, and the “dispersion” of NC is governed by that of LS. Therefore, the dispersion of nano-CaCO3 can be improved by the NC/LS in cementitious materials. In this work, the preparation of NC/LS was carried out in a three-necked flask using the Ca(OH)2-H2O-CO2 reaction system. The morphology of NC/LS was observed by a field emission scanning electron microscope (FE-SEM). The effects of NC/LS on the hydration products and pore structure of cementitious materials are proposed. 5% NC/LS was added into cement paste and mortar, and the mechanical properties of the specimens were measured at a certain age. Differential scanning calorimetry (DSC), thermal gravimetric analysis (TG), and backscattered electron imaging (BSE) were conducted on the specimens to investigate the hydration products and pore structure. The properties of specimens with NC/LS were compared to that of control specimens (without NC/LS). The results revealed that NC/LS reduced the porosity and improved the mechanical properties of the cementitious materials.

Download Full-text

Micro-Pore Structure and Mechanical Properties of High Temperature Self-Lubricating Biomimetic TiC/FeCrWMoV Cermets

Materials Science Forum ◽

10.4028/www.scientific.net/msf.546-549.2273 ◽

2007 ◽

Vol 546-549 ◽

pp. 2273-2278 ◽

Cited By ~ 2

Author(s):

Yan Jun Wang ◽

Zuo Min Liu

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Powder Metallurgy ◽

Pore Structure ◽

Network Structure ◽

Sweat Gland ◽

Solid Lubricant ◽

Rayleigh Distribution

A new cermet sinter with sweat-gland micro-pore structure has been developed by powder metallurgy technology in vacuum. The effects of the pore-forming materials on micro-pore structure and Y2O3 additions as well mechanical properties of TiC/FeCrWMoV cermets were investigated. Some typical sweat-gland micro-pores were formed while compound additives TiH2 and CaCO3 adding into the sinter matrix. The porosity of the cermet sinters changes from 20% to 28% with the compound additives from 6% to 8%, and the micro-pores of sinters exist a regularized and interpenetrated network structure just like human’s sweat-gland one and obeying to Rayleigh Distribution. As such the sinters could be easily infiltrated with high-temperature solid lubricant. For improving the property of the ceramet sinter, the elements Y2O3 of 0.6～0.8% (vol. fraction ) was also added into the sinter matrix and its effect on the sinter has been also discussed .

Download Full-text