scholarly journals CO2 Uptake and Physicochemical Properties of Carbonation-Cured Ternary Blend Portland Cement–Metakaolin–Limestone Pastes

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4656
Author(s):  
Rizwan Hameed ◽  
Joonho Seo ◽  
Solmoi Park ◽  
Issam T. Amr ◽  
H.K. Lee

The feasibility of carbonation curing of ternary blend Portland cement–metakaolin–limestone was investigated. Portland cement was substituted by the combination of metakaolin and limestone at levels of 15%, 30%, and 45% by the mass. The ternary blends were cured with four different combinations of ambient and carbonation curing. The mechanical property, CO2 uptake, and mineralogical variations of the ternary blend pastes were investigated by means of compressive strength test, thermogravimetric analysis, and X-ray diffractometry. In addition, volume of permeable voids and sorptivity of the ternary blends were also presented to provide a fundamental idea of the pore characteristics of the blends. The test results showed that the increasing amount of metakaolin and limestone enhanced the CO2 uptake, reaching 20.7% for the sample with a 45% cement replacement level at 27 d of carbonation. Meanwhile, the compressive strength of the samples was reduced up to 65% upon excessive incorporation of metakaolin and limestone. The samples with a replacement level of 15% exhibited a comparable strength and volume of permeable voids to those of the sample without substitution, proving that the ternary blend Portland cement–metakaolin–limestone can be a viable option toward the development of eco-friendly binders.

2013 ◽  
Vol 838-841 ◽  
pp. 42-46 ◽  
Author(s):  
Jun Jie Zeng ◽  
Zhi Hong Fan ◽  
Long Chen

The influence of metakaolin (MK) on strength and microstructure of steam-cured high-strength concrete has been investigated using compressive strength test, XRD, MIP and SEM. Three MK replacement levels were considered in the study: 5%, 10% and 15% by weight of cement. A mix double blended with 10% MK and 10% slag was prepared too. Test results have indicated that MK can increase the compressive strength of steam-cured concrete, especially at early age. Compressive strength up to 90MPa at 1 and 28 days is obtained with the incorporation of 10% MK and 10% slag. When the replacement level of MK is higher than 10%, the enhancement of strength becomes less significant. Content of Ca (OH)2 crystals is decreased while content of hydrates with Al is increased due to the pozzolanic reactivity of MK. Concrete pore structure is significantly refined and a denser hydrates structure is obtained due to the pozzolanic reaction and filler effect of MK. Meanwhile, combination of aggregate and paste is enhanced too. The improvements of strength and microstructure become more obvious when MK and slag are double incorporated.


2014 ◽  
Vol 936 ◽  
pp. 1382-1386
Author(s):  
Guo Cai Wang ◽  
Lin Chun Yu ◽  
Ling Sha

In order to study the inorganic composite curing agents of lime, gypsum, fly ash on the strength properties of EPS lightweight soil using recycled sludge, the unconfined compressive strength test and scanning electron microscope test are done to investigate the strength properties of EPS lightweight soil. The effect and scope of each curing agent is investigated and determined by means of single-doped unconfined compressive strength test, and the optimum proportion of the curing agent is further determined by the method of orthogonal unconfined compressive strength test, of which the stabilized effectiveness of the lightweight soil is compared with those only using cement as curing agent. Finally, the SEM test is done to study the microstructure and pore characteristics of the lightweight soil mixed with EPS adding with or without curing agent. The test results and curing agent can be used as conference when stabilizing soft soil and treatment of discarded clay.


2019 ◽  
Vol 11 (1) ◽  
pp. 7-12
Author(s):  
Hotmalina Manullang ◽  
Fepy Supriani ◽  
Agustin Gunawan

Mortar is a mixture of adhesive (Portland cement and limestone), sand, and water with a certain composition. Mortar is used in structural and nonstructural constructions. This research uses sawdust charcoal as cement addition because in similar research mention that wood charcoal contains silica. This research was aimed to know the value of compressive strength of the mortar (1:3 and 1:5) by using sawdust charcoal as cement addition. The method of manufacture and testing compressive strength of mortar refers to SNI 03-6825-2002. The mortar specimens is cube shaped with side 50 mm and the total of specimens have 112 mortar test specimens. Variations of sawdust charcoal used were 2,5%, 5%, 7,5%, 10%, 12,5% and 15% of the weight of cement. The range of initial flow values used are 105% - 115 (SNI 03-6882-2002). The specimens were soaked for 26 days and compressive strength test of mortar was performed at 28 days. The test results showed that the compressive strength value of normal mortar (1:3) of 25,09 MPa, the value of compressive strength of variation mortar 2,5%, 5%, 7,5%, 10%, 12,5% and 15% respectively are 25,89 MPa, 26,93 MPa, 27,84 MPa, 25,58 MPa, 20,68 MPa and 17,24 MPa. The value of compressive strength of normal mortar (1:5) of 15,48 MPa, the value of compressive strength of mortar variation 2,5%, 5%, 7,5%, 10%, 12,5% and 15% respectively are 15,83 MPa, 16,24 MPa, 17,01 MPa, 15,59 MPa, 14,45 MPa dan 12,26 MPa. The highest increase of compressive strength value in mixture 1:3 was variation 7,5% by 10,94% and mixture 1:5 was variation 7,5% by 9,90% from the compressive strength value of normal mortar.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Sumrerng Rukzon ◽  
Prinya Chindaprasirt

This paper presents the use of blend of Portland cement with rice husk-bark ash in producing self-compacting concrete (SCC). CT was partially replaced with ground rice husk-bark ash (GRHBA) at the dosage levels of 0%–40% by weight of binder. Compressive strength, porosity, chloride penetration, and corrosion of SCC were determined. Test results reveal that the resistance to chloride penetration of concrete improves substantially with partial replacement of CT with a blend of GRHBA and the improvement increases with an increase in the replacement level. The corrosion resistances of SCC were better than the CT concrete. In addition, test results indicated that the reduction in porosity was associated with the increase in compressive strength. The porosity is a significant factor as it affects directly the durability of the SCC. This work is suggested that the GHRBA is effective for producing SCC with 30% of GHRBA replacement level.


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2372
Author(s):  
Yesenia Sánchez-Cardona ◽  
Claudia E. Echeverri-Cuartas ◽  
Marta E. Londoño López ◽  
Natalia Moreno-Castellanos

Chitosan scaffolds based on blending polymers are a common strategy used in tissue engineering. The objective of this study was evaluation the properties of scaffolds based on a ternary blend of chitosan (Chi), gelatin (Ge), and polyvinyl alcohol (PVA) (Chi/Ge/PVA), which were prepared by cycles of freeze-thawing and freeze-drying. It then was used for three-dimensional BRIN-BD11 beta-cells culturing. Weight ratios of Chi/Ge/PVA (1:1:1, 2:2:1, 2:3:1, and 3:2:1) were proposed and porosity, pore size, degradation, swelling rate, compressive strength, and cell viability analyzed. All ternary blend scaffolds structures are highly porous (with a porosity higher than 80%) and interconnected. The pore size distribution varied from 0.6 to 265 μm. Ternary blends scaffolds had controllable degradation rates compared to binary blend scaffolds, and an improved swelling capacity of the samples with increasing chitosan concentration was found. An increase in Young’s modulus and compressive strength was observed with increasing gelatin concentration. The highest compressive strength reached 101.6 Pa. The MTT assay showed that the ternary blends scaffolds P3 and P4 supported cell viability better than the binary blend scaffold. Therefore, these results illustrated that ternary blends scaffolds P3 and P4 could provide a better environment for BRIN-BD11 cell proliferation.


Author(s):  
Edward Dinoy ◽  
Yohanes Gilbert Tampaty ◽  
Imelda Srilestari Mabuat ◽  
Joseph Alexon Sutiray Dwene

The compressive strength test is one of the technical properties or compressive strength tests that are commonly used in rock mechanics to determine the collapse point or the elasticity of rock against maximum pressure. The rock collapse point is a measure of the strength of the rock itself when the rock is no longer able to maintain its elastic properties. The purpose of this test is to find out how long the rock maintains its strength or elasticity properties when pressure is applied, and to find out the difference between the strength of compact rock and rock that has fractures when pressure is applied. Rocks that have fractures will break more easily or quickly when pressure is applied compared to compact rocks. This analysis is carried out by comparing the rock strength of each sample, both those that have fractures and compact rocks. To find out these differences, laboratory testing was carried out. The test results show the value (compressive strength test 57.76 MPa), (elastic modulus 5250.000MPa), (Poisson ratio 0.05) and the average value of rock mechanical properties test (axial 0.91), (lateral-0.279), and (volumetric 0.252) . Based on the test results above, it shows that rocks that have fractures will break more easily when pressure is applied, compared to compact rocks that have a long time in the uniaxial compressive strength test.


2020 ◽  
Vol 323 ◽  
pp. 01018
Author(s):  
Wei-Ting Lin ◽  
Lukáš Fiala ◽  
An Cheng ◽  
Michaela Petříková

In this study, the different proportions of co-fired fly ash and ground granulated blast-furnace slag were used to fully replace the cement as non-cement blended materials in a fixed water-cement ratio. The recycled fine aggregates were replaced with natural fine aggregates as 10%, 20%, 30%, 40% and 50%. The flowability, compressive strength, water absorption and scanning electron microscope observations were used as the engineered indices by adding different proportions of recycled fine aggregates. The test results indicated that the fluidity cannot be measured normally due to the increase in the proportion of recycled fine aggregates due to its higher absorbability. In the compressive strength test, the compressive strength decreased accordingly as the recycled fine aggregates increased due to the interface structure and the performance of recycled aggregates. The fine aggregates and other blended materials had poor cementation properties, resulting in a tendency for their compressive strength to decrease. However, the compressive strength can be controlled above 35 MPa of the green non-cement blended materials containing 20% recycled aggregates.


2021 ◽  
Author(s):  
Palash Badjatya ◽  
Abdullah Akca ◽  
Daniela Fraga Alvarez ◽  
Baoqi Chang ◽  
Siwei Ma ◽  
...  

This study describes and demonstrates a carbon-negative process for manufacturing cement from widely abundant seawater-derived magnesium (Mg) feedstocks. In contrast to conventional Portland cement, which starts with carbon-containing limestone as the source material, the proposed process uses membrane-free electrolyzers to facilitate the conversion of carbon-free magnesium ions (Mg2+) in seawater into magnesium hydroxide (Mg(OH)2) precursors for the production of Mg-based cement. After a low-temperature carbonation curing step converts Mg(OH)2 into magnesium carbonates through reaction with carbon dioxide (CO2), the resulting Mg-based binders can exhibit compressive strength comparable to that achieved by Portland cement after curing for only two days. Although the proposed “cement-from-seawater” process requires similar energy use per ton of cement as existing processes, its potential to achieve a carbon-negative footprint makes it highly attractive to decarbonize one of the most carbon intensive industries.


Author(s):  
Sravya Nalla ◽  
Janardhana Maganti ◽  
Dinakar Pasla

Self-compacting concrete (SCC) is a revolutionary development in concrete construction. The addition of mineral admixtures like metakaolin, which is a highly reactive pozzolana to the SCC mixes, gives it superior strength and durability. The present work is an effort to study the behavior of M50 grade SCC by partial replacement of Portland Slag Cement (PSC) with metakaolin. Its strength and durability aspects are comparable with a controlled concrete (without replacement of cement). In the present work, a new mix design methodology based on the efficiency of metakaolin is adopted. The optimum percentage replacement of cement with metakaolin is obtained based on compressive strength test results. The influence of metakaolin on the workability, compressive strength, splitting tensile strength and flexural strength of SCC and its behavior when subjected to elevated temperature was investigated through evaluation against controlled concrete and non-destructive testing. From the test results, it was observed that incorporation of metakaolin at an optimum dosage satisfied all the fresh properties of SCC and improved both the strength and durability performance of SCC compared to controlled concrete.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Alireza Mohammadi Bayazidi ◽  
Gai-Ge Wang ◽  
Hamed Bolandi ◽  
Amir H. Alavi ◽  
Amir H. Gandomi

This paper presents a new multigene genetic programming (MGGP) approach for estimation of elastic modulus of concrete. The MGGP technique models the elastic modulus behavior by integrating the capabilities of standard genetic programming and classical regression. The main aim is to derive precise relationships between the tangent elastic moduli of normal and high strength concrete and the corresponding compressive strength values. Another important contribution of this study is to develop a generalized prediction model for the elastic moduli of both normal and high strength concrete. Numerous concrete compressive strength test results are obtained from the literature to develop the models. A comprehensive comparative study is conducted to verify the performance of the models. The proposed models perform superior to the existing traditional models, as well as those derived using other powerful soft computing tools.


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