Strength Loss Method to Evaluate the Sulfate Attack Resistance of the Cement-Porous Silica Fume Mortar

2014 ◽  
Vol 576 ◽  
pp. 133-141
Author(s):  
Shou Qi Zhang ◽  
Shu Xiong Zhang ◽  
Yu Fang Fu ◽  
Dong Min Wang
Keyword(s):  
Silica Fume ◽  
Cement Mortar ◽  
Porous Silica ◽  
Acid Leaching ◽  
Strength Loss ◽  
Sulfate Attack ◽  
Holding Time ◽  
Mineral Admixture ◽  
Material Development ◽  
Asbestos Tailings

The key factors for activity of asbestos tailings acid leaching residue (ATALR) and activated process were researched by the way of orthoplan, so as to make a new type of high-active mineral admixture in cement-based material, named as porous silica fume (PSF). Then with the strength loss indexes designed, the sulfate attack resistance of cement-PSF mortars was evaluated, which was dunked in solution of sodium sulfate during from 6 to 12 months. The results indicated that thermal activated temperature and holding time was the key factor for compressive strength, while holding time and grinding time for flexural strength. The optimal activated process was the thermal activated temperature at800°C needing to hold for 1 hour before grinding for 20minuteswhilethe appropriate amount of PSF was 5%~12% in cement mortar. When 5%~8% PSF contained, the sulfate attack resistance of cement mortar can be improved obviously, and the role was similar to silica fume (SF). PSF activated from ATALR is helpful for resource utilization of asbestos tailings, in order to improve ecological environment in the asbestos mine town and promote cement-based material development.

Sulfate attack and role of silica fume in resisting strength loss

2005 ◽  
Vol 27 (1) ◽  
pp. 65-76 ◽  
Author(s):  
S.T. Lee ◽  
H.Y. Moon ◽  
R.N. Swamy
Keyword(s):  
Silica Fume ◽  
Strength Loss ◽  
Sulfate Attack

Experiment and Research on the Influence of Mineral Admixture on Cement-Based Material Performance

2012 ◽  
Vol 174-177 ◽  
pp. 1446-1449 ◽  
Author(s):  
Xiao Hong Cong ◽  
Bin Xue ◽  
Jing Sun ◽  
Xiao Wei Sun
Keyword(s):  
Compressive Strength ◽  
Data Analysis ◽  
Fly Ash ◽  
Silica Fume ◽  
Cement Mortar ◽  
Mineral Admixture ◽  
Basic Material ◽  
Mixture Ratio

Cement mortar as the basic material and the fly ash and silicon fume as the research object, experiment and research were operated through adjusting the admixture replacing dosage and changing the mixture ratio of silica fume and fly ash. By testing the fluidity and strength and data analysis and discussion, some conclusions are drawn from the analysis, such as: fly ash makes the fluidity increasing with the admixture replacing dosage below 30%, and the fluidity declines with the mixture ratio of silica fume and fly ash increasing. 7d compressive strength decreases with the admixture replacing dosage increasing, 7d compressive strength increases slowly with the mix ratio of silica fume and fly ash. With the mix ratio of silica fume and fly ash increasing, 28d compressive strength of mortar also increases, and proper mix ratio of silica fume and fly ash is 1:1.

Study on the Mechanical Properties and Frost Resistance of Recycled Concrete Prepared by Village Construction Wastes

2011 ◽  
Vol 418-420 ◽  
pp. 406-410
Author(s):  
Jun Liu ◽  
Yao Li ◽  
Dan Dan Hong ◽  
Yu Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Frost Resistance ◽  
Cement Mortar ◽  
Strength Loss ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Replacement Rate ◽  
Concrete Mechanical Properties ◽  
Better Than

Abstract. Recycled aggregate—rural building material wastes pretreated by cement mortar—are applied into concrete with different replacement rates: 0, 25%, 50%, 75%, and 100%. Results from measurements of compressive strength, cleavage tensile strength, mass loss after fast freeze-thaw cycles, and compressive strength loss indicate that a different recycled aggregate replacement rate certainly influences concrete mechanical properties and frost resistance. Recycled aggregate replacement rates less than 75% performs better than common concrete. Data from the 100% replacement rate is worse than that of rates less than 75% but still satisfy the general demands of GB standard on C30 concrete.

scholarly journals Evaluating the Durability of Green Cement Mortar Using Ultrasonic Pulse Velocity

2021 ◽  
Vol 877 (1) ◽  
pp. 012049
Author(s):  
Ali Abdulridha ◽  
Saif S. AlQuzweeni ◽  
Rasha S. AlKizwini ◽  
Zahra A. Saleh ◽  
K. S. Hashem
Keyword(s):  
Silica Fume ◽  
Cement Mortar ◽  
Experimental Studies ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Negative Consequences ◽  
Kiln Dust

Abstract Various experimental studies have highlighted the negative consequences of Portland cement on health and the environment, such as toxic emissions and alkaline sewage. The development of environmentally acceptable substitutes for cement is thus one of the objectives of current investigations. The proposed environmental alternatives to cement, nevertheless, might have detrimental impacts on the concrete’s characteristics. This investigation intends to study the suitability as alternatives to cement in cement mortar, using industrial wastes like silica fume and cement kiln dust. As a replacement for cement, the cement mortars developed in this research continue from 0% to 60% silica fume and cement kiln dust. Ultrasonic pulse velocity tests at 1 to 4 weeks of age were conducted on hardened specimens. The findings showed that a low reduction in the pulse velocity resulted from high proportions of silica fume and cement kiln dust replacements, whereas an improvement in the characteristics of the mortars with low replacement ratios. Using low kiln dust and silica fume of 20 to 40%, the durability of mortars may increase.

Study on Sulfate Resistance of Concrete with Compound Mineral Admixture

2011 ◽  
Vol 99-100 ◽  
pp. 420-425 ◽  
Author(s):  
Qian Rong Yang ◽  
Xiao Qian Wang ◽  
Hui Ji
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Steel Slag ◽  
Sulfate Attack ◽  
Mineral Admixture ◽  
Sulfate Resistance ◽  
Chemical Attack ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

The strength, expansion and amount of scaling of concrete with compound mineral admixture (CMA) from steel slag, granulated blast furnace slag and fly ash were studied. The result shows that damage by crystallization press from sulfate attack when concrete was exposed to sulfate environments under wetting–drying alternation is much larger than that from sulfate chemical attack. Adding CMA to concrete could reduce the damage from expansion of concrete caused by sulfate chemical attack, but the resistance of concrete to damage by crystallization press from sulfate attack was remarkably reduced.

Some Properties of Cement Mortar Incorporating Micro and Nano-Metakaolin Materials

2021 ◽  
Vol 1021 ◽  
pp. 231-240
Author(s):  
Manolia Abed Al-Wahab Ali ◽  
Mohammed Jawad Kadhim ◽  
Ibtesam F. Nasser
Keyword(s):  
Flexural Strength ◽  
Greenhouse Gas Emission ◽  
Cement Mortar ◽  
Physical And Mechanical Properties ◽  
Pozzolanic Reaction ◽  
Mineral Admixture ◽  
Concrete Technology ◽  
Binder Ratio ◽  
Substitution Ratio ◽  
High Production

There are many reasons neededfor continuous evolution in concrete technology; one of them concern on the greenhouse gas emission and depletion of natural resource as a results of high production of Portland cement. Many solutions are used to solve these problems; one of them is using cement replacement materials in concrete like metakaolin (in micro or Nano scale) which offered positive effect on the properties of cement concrete. Therefore, the main aim of this study is to evaluate and compare the effects of metakaolin (MK) and Nano-metakaolin (NMK) on some physical and mechanical properties of cement mortar. For this purpose, mortar mixes are prepared by substituting cement (by weight) with (10%) metakaolin or (1, 3, 5, and 7%) Nano - metakaolin. The amount of binder for mortar mixtures is 700 kg/m with a constant water / binder ratio of 0.33. Workability, apparent density, water absorption, compressive strength, and flexural strength of all mortar mixes are determined and compared with reference mix without any mineral admixture (0% MK or NMK). The results indicated that the performance of mortar mixes can be enhanced by metakaoline replacement. Furthermore, Nano-metakaolin has significantly positive impacts on the properties of mortar mixes which have found to be improved with increasing the Nano-metakaolin replacement, due to better pore refinement, micro filling action, and higher pozzolanic reaction. The optimum Nano-metakaolin substitution ratio (7%) causes increase in compressive and flexural strength reach to (82.6% and 59.5%), respectively compared with the reference mix, at age of 28 days.

scholarly journals Mechanical Properties and Microscopic Mechanism of Coral Sand-Cement Mortar

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Luoxin Wang ◽  
Junshuai Mei ◽  
Jing Wu ◽  
Xingyang He ◽  
Hainan Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cement Mortar ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Hardened Cement ◽  
Hydration Reaction ◽  
Microscopic Mechanism ◽  
X Ray ◽  
Volume Stability ◽  
Coral Sand

The workability and mechanical performance of coral sand-cement mortar (coral mortar, for short) and the modification effects of mineral admixtures on the coral mortar were studied in this paper. The results showed that the strength of coral mortar was lower than that of standard mortar, but the strength of coral mortar was improved by compositing with the mineral admixture, which can be attributed to the improvement of the microstructure and interface transition area. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to explore the microscopic mechanism involved in the mechanical properties, volume stability, and hydration of mortar. The analyses revealed that the internal curing effect of coral sand improved the mechanical properties of mortar and its ability to resist shrinkage. The uneven surface of coral sand formed a meshing state of close combination with the hardened cement mortar, which helped to improve the volume stability of mortar. The Ca2+ and Mg2+ ions from coral sand participated in the hydration reaction of cement, which contributed to generating more hydration products. Moreover, the microaggregate filling and pozzolanic effects of fly ash and slag improved the mechanical properties of coral mortar and resistance to chloride ion diffusion.

The Mechanism of Mineral Admixture in Cement Hydration

2012 ◽  
Vol 450-451 ◽  
pp. 1528-1531
Author(s):  
Mei Li Zhao
Keyword(s):  
Cement Paste ◽  
High Performance ◽  
Cement Hydration ◽  
High Performance Concrete ◽  
Cement Mortar ◽  
Sem Analysis ◽  
Mineral Admixture ◽  
Hydration Mechanism ◽  
Curing Period ◽  
Durability Performance

The mineral admixture is one of the indispensable materials for ordinary high-performance concrete. In this paper, the pure cement paste and cement paste replacing by mineral admixture were tested by cement mortar. The SEM analysis of pure cement paste and mineral admixture paste after curing period of 7 days and 28 days.From the picture of SEM after the period of 7 days and 28 days,the cement hydration mechanism was suspected.It could be used for explanating the physical performance and durability performance of the high perfromance concrete with mineral admixture.

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