scholarly journals Chloride Diffusion by Build Orientation of Cementitious Material-Based Binder Jetting 3D Printing Mortar

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7452
Author(s):  
Kyung-Sung Min ◽  
Kwang-Min Park ◽  
Bong-Chun Lee ◽  
Young-Sook Roh
Keyword(s):  
Compressive Strength ◽  
3D Printing ◽  
Transverse Direction ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Building Structures ◽  
Reinforcing Bars ◽  
Build Orientation ◽  
Strength And Durability ◽  
Binder Jetting

Binder jetting 3D printing (BJ3DP) is used to create geometrical and topology-optimized building structures via architectural geometric design owing to its high degree of freedom in geometry implementation. However, building structures require high mechanical and durability performance. Because of the recent trend of using 3D printing concrete as a structural component in reinforcing bars, its durability with respect to chloride penetration needs to be reviewed. Therefore, in this study, the compressive strength and durability of the chloride diffusion of cement-based 3D-printed output were evaluated. In addition, to confirm the performance difference based on the build orientation, the compressive strength and chloride diffusion were evaluated with respect to the build direction and transverse direction. The experimental results show that the compressive strength was approximately 22.1–26.5% lower in the transverse direction than in the build direction and that the chloride diffusion coefficient was approximately 186.1–407.1% higher in the transverse direction. Consequently, when a structure that requires long-term durability is produced using BJ3DP, it is necessary to examine the design and manufacturing methods in relation to the build orientation in advance.

scholarly journals Effects of Nanosilica on Compressive Strength and Durability Properties of Concrete with Different Water to Binder Ratios

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Forood Torabian Isfahani ◽  
Elena Redaelli ◽  
Federica Lollini ◽  
Weiwen Li ◽  
Luca Bertolini
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Reference Value ◽  
Chloride Diffusion ◽  
Gravimetric Analysis ◽  
Chloride Diffusion Coefficient ◽  
X Ray Diffraction ◽  
Durability Properties ◽  
Water Sorptivity ◽  
Strength And Durability

The effects of the addition of different nanosilica dosages (0.5%, 1%, and 1.5% with respect to cement) on compressive strength and durability properties of concrete with water/binder ratios 0.65, 0.55, and 0.5 were investigated. Water sorptivity, apparent chloride diffusion coefficient, electrical resistivity, and carbonation coefficient of concrete were measured. The results showed that compressive strength significantly improved in case of water/binder = 0.65, while for water/binder = 0.5 no change was found. Increasing nanosilica content, the water sorptivity decreased only for water/binder = 0.55. The addition of 0.5% nanosilica decreased the apparent chloride diffusion coefficient for water/binder = 0.65 and 0.55; however, higher nanosilica dosages did not decrease it with respect to reference value. The resistivity was elevated by 0.5% nanosilica for all water/binder ratios and by 1.5% nanosilica only for water/binder = 0.5. The carbonation coefficient was not notably affected by increasing nanosilica dosages and even adverse effect was observed for water/binder = 0.65. Further information of microstructure was also provided through characterization techniques such as X-ray diffraction, thermal gravimetric analysis, mercury intrusion porosimetry, and scanning electron microscopy. The effectiveness of a certain nanosilica dosage addition into lower strength mixes was more noticeable, while, for the higher strength mix, the effectiveness was less.

Influence of the Nanomaterials of Kaolin Content on the Chloride Permeability of Cement Mortar

2017 ◽  
Vol 730 ◽  
pp. 406-411 ◽  
Author(s):  
Xiao Yu Guo ◽  
Ying Fang Fan ◽  
Kun Yang
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Cement Mortar ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Permeability

This study investigated the influence of nanokaolin content on the behavior of cement mortar at various curing ages. The fluidity, chloride permeability, bending and compressive strength of cement mortar with various nanokaolin additives were examined. The addition of 0%, 1%, 2%, 3%, 4%, 5% and 6% nanokaolin were taken into consideration. The results showed that the addition of nanokaolin decreases the fluidity of cement mortar, and the fluidity the cement mortar decreases with the increase of nanokaolin additives. It is obtained that the addition of nanokaolin increases both the bending and compressive strength of cement mortar, and with the increase of nanokaolin additives, the bending and compressive strength of cement mortar increase. The addition of 4% nanokaolin can result in a significant low chloride permeability of cement mortar among the seven dosages. The chloride diffusion coefficient of the mortar with the addition of 4% nanokaolin was decreased by 18.93%, 12.68% and 31.05% at 7, 14 and 28 curing days, respectively.

scholarly journals Influence of Parent Concrete Properties on Compressive Strength and Chloride Diffusion Coefficient of Concrete with Strengthened Recycled Aggregates

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4631 ◽  
Author(s):  
Jingwei Ying ◽  
Zewen Han ◽  
Luming Shen ◽  
Wengui Li
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Water Absorption ◽  
Recycled Aggregates ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Wide Range ◽  
Different Types ◽  
Compressive Strength Of Concrete ◽  
Silica Slurry

Parent concrete coming from a wide range of sources can result in considerable differences in the properties of recycled coarse aggregate (RCA). In this study, the RCAs were obtained by crushing the parent concrete with water-to-cement ratios (W/Cparent) of 0.4, 0.5 and 0.6, respectively, and were strengthened by carbonation and nano-silica slurry wrapping methods. It was found that when W/Cparen was 0.3, 0.4 and 0.5, respectively, compared with the mortar in the untreated RCA, the capillary porosity of the mortar in the carbonated RCA decreased by 19%, 16% and 30%, respectively; the compressive strength of concrete containing the carbonated RCA increased by 13%, 11% and 13%, respectively; the chloride diffusion coefficient of RAC (DRAC) containing the nano-SiO2 slurry-treated RCA decreased by 17%, 16% and 11%; and that of RAC containing the carbonated RCA decreased by 21%, 25% and 26%, respectively. Regardless of being strengthened or not, both DRAC and porosity of old mortar in RCAs increased with increasing W/Cparent. For different types of RCAs, DRAC increased obviously with increasing water absorption of RCA. Finally, a theoretical model of DRAC considering the water absorption of RCA was established and verified by experiments, which can be used to predict the DRAC under the influence of different factors, especially the water absorption of RCA.

scholarly journals Evaluation of Chloride Resistance of Early-Strength Concrete Using Blended Binder and Polycarboxylate-Based Chemical Admixture

2020 ◽  
Vol 10 (8) ◽  
pp. 2972 ◽  
Author(s):  
Taegyu Lee ◽  
Jaehyun Lee
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Portland Cement ◽  
Chloride Ion ◽  
Strength Criterion ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Characteristic Strength ◽  
Early Strength

The mixing proportions of concrete were examined with regard to the durability performance and early strength in coastal areas. Research was conducted to improve the C24 mix (characteristic strength of 24 MPa). C35 concrete (characteristic strength of 35 MPa) was selected as a comparison group, as it exhibits the minimum proposed strength criterion for concrete in the marine environment. To secure the early strength of the C24 concrete, 50% of the total ordinary Portland cement (OPC) binder was replaced with early Portland cement (EPC); and to provide durability, 20% was substituted with ground granulated blast-furnace slag (GGBS). In addition, a polycarboxylate (PC)-based superplasticizer was used to reduce the unit water content. The compressive strength, chloride ion diffusion coefficient, chloride penetration depth, and pore structure were evaluated. After one day, the compressive strength improved by 40% when using EPC and GGBS, and an average increase of 20% was observed over 91 days. EPC and GGBS also reduced the overall porosity, which may increase the watertightness of concrete. The salt resistance performance was improved because the rapid early development of strength increased the watertightness of the surface and immobilization of chloride ions, decreasing the chloride diffusion coefficient by 50%.

scholarly journals Engineering Properties of Ternary Cementless Blended Materials

2020 ◽  
Vol 10 (3) ◽  
pp. 191-199
Author(s):  
Wei-Ting Lin ◽  
Kinga Korniejenko ◽  
Marek Hebda ◽  
Michał Łach ◽  
Janusz Mikuła
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Engineering Properties ◽  
Chloride Diffusion ◽  
Total Charge ◽  
Chloride Diffusion Coefficient ◽  
Furnace Slag

A new non-cement blended materials is developed as a full replacement of cement without alkali activator. This study was conducted to explore a suitable method for activating new ternary green materials with desulfurization gypsum, water-quenched blast-furnace slag and co-fired fly ash from circulating fluidized bed combustion as non-cement inorganic binder. Test subject was included flowability, compressive strength, absorption, total charge-passed from rapid chloride permeability test, chloride diffusion coefficient from accelerated chloride migration test and SEM observation. Test results indicate that a ternary mixture containing 1% desulfurization gypsum, 60% water-quenched blast-furnace slag and 39% co-fired fly ash was a suitable development in compressive strength. The new non-cement blended materials were performed a well compressive strength, lower absorption, and lower chloride diffusion coefficient. In addition, the compressive strength decreased as the inclusion of desulfurization gypsum increased. It was concluded that using desulfurization gypsum alone decreased the setting time and compressive strength. SEM micrographs were verified the development in compressive strength originated from the C-S-H and C-A-S-H gel produced by Ca(OH)2, SiO2, and Al2O3.

Effect of Build Orientation on Mechanical Properties of Rapid Prototyping (Fused Deposition Modelling) Made Acrylonitrile Butadiene Styrene (ABS) Parts

2013 ◽  
Author(s):  
K. M. Ashtankar ◽  
A. M. Kuthe ◽  
Bechu Singh Rathour
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Rapid Prototyping ◽  
Transverse Direction ◽  
Axial Direction ◽  
Compression Testing ◽  
Fused Deposition Modelling ◽  
Type I ◽  
Build Orientation ◽  
Fused Deposition

Prototyping is the process of building pre-production models of a product to test various aspects of its design. Fused deposition modeling (FDM) is a process for developing rapid prototype (RP) objects by depositing fused layers of material according to numerically defined cross sectional geometry. The quality of FDM produced parts is significantly affected by various parameters used in the process. This paper aims to study the effect of one such parameter i.e., build orientation, on mechanical properties (mainly tensile and compressive strength) of FDM processed parts. In rapid prototyping (FDM), the orientation of the parts during fabrication is critical as it can affect part strength such as tensile and compressive strength. Specimens are prepared for tensile/compression test as per ASTM standards. It was found that the build orientation of the specimen has more of an impact on strength. The layering build process of rapid prototyping creates a variance in strength depending on the build orientation. The D695 standard allows for stable compression testing and is used for compression testing. Several geometries are allowed for tension specimens under the D638 standard. We chose the type I specimen as it is the most commonly used and best fit our mechanical testing equipment. From the tensile test result, it is found that when build orientation is increasing from 0° to 90°, ultimate tensile strength decreases. It is maximum at 0° orientation i.e., 15.2 MPa and minimum at 90° orientation i.e., 11.6 MPa. The tensile stress at 0° (i.e. axial direction) is 23.68 % higher than transverse direction (i.e., 90°). From the compressive test results, it is found that, when sample orientation is increasing from 0° to 90°, the ultimate compressive strength decreases. It is maximum at 0° orientation i.e., 26.66 MPa and minimum at 90° orientation i.e., 22.22 MPa. The compressive stress at 0° (i.e. axial direction) is 16.65 % higher than transverse direction (i.e. 90°).

Behavioral Prediction of Reactive Powder Concrete Based on Artificial Neural Network

2010 ◽  
Vol 168-170 ◽  
pp. 1030-1033
Author(s):  
Tao Ji ◽  
Yi Zhou Zhuang ◽  
Bao Chun Chen ◽  
Zhi Bin Huang
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Chloride Diffusion ◽  
Reactive Powder Concrete ◽  
Chloride Diffusion Coefficient ◽  
Binder Ratio ◽  
Artificial Neural ◽  
Reactive Powder

Based on orthogonal array testing strategy (OATS), the effects of sand-binder ratio (S/B), water-binder ratio (W/B), and the ratio of steel fiber volume to reactive powder concrete (RPC) volume (STF/R) on the compressive strength and chloride diffusion coefficient of RPC were investigated using an artificial neural network method. Research results reveal that the compressive strength of RPC approaches summit when STF/R is 2% or W/B is 0.18-0.2%, and decreases with the increasing of S/B. Furthermore, the chloride diffusion coefficient increases with W/B or STF/R and decreases with S/B.

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