scholarly journals Influence of Some Additives on the Properties of OPC Solidified Sandy Silt

2021 ◽  
Vol 11 (16) ◽  
pp. 7252
Author(s):  
Dazhi Wu ◽  
Keyu Chen ◽  
Zilong Zhang ◽  
Lifu Chang

The ordinary Portland cement (OPC)-based solidification process is used extensively to reinforce soils due to its available and good bonding properties. Alternative products are used in cementitious materials to enhance the strength and to reduce OPC consumption. In this study, the effect of additive type and mass fraction on the microstructure and mechanical properties of solidified sandy silt are investigated. There are four types of additives (gypsum, lime, clay particles, and fly ash) at mass fractions of 2, 3, and 4% that are considered in order to study their mechanical properties (unconfined compression, indirect tensile, flexural strength, and compressive resilient modulus) at 7, 14, 28, 60, and 90 days. The optimal contents of additive gypsum, clay particles, and fly ash are determined to be 2%, 4%, and 4%, respectively. Such improvement of additive-modified OPC solidified sandy silt is due to the formation of the crystalline compound or the gradation composition improvement via field emission scanning electron and X-ray diffraction analysis.

2017 ◽  
Vol 866 ◽  
pp. 199-203
Author(s):  
Chidchanok Chainej ◽  
Suparut Narksitipan ◽  
Nittaya Jaitanong

The aims of this research were study the microstructures and mechanical properties for partial replacement of cement with Fly ash (FA) and kaolin waste (KW). Ordinary Portland cement were partially replaced with FA and KW in the range of 25-35% and 10-25% by weight of cement powder. The kaolin waste was ground for 180 minutes before using. The specimen was packing into an iron mold which sample size of 5×5×5 cm3. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the incubation lime water bath at age of 3 days. After that the specimens were dry cured with plastic wrap at age of 3, 7, 14 and 28 days. After that the compounds were examined by x-ray diffraction patterns (XRD) and the microstructures were examined by scanning electron microscopy (SEM). The compressive strength was then investigated.


2018 ◽  
Vol 25 (4) ◽  
pp. 707-714 ◽  
Author(s):  
Yuefang Zhang ◽  
Shunhua Liu ◽  
wanJun Hao

Abstract Double-layer absorbing cement-based composites with the thickness of 10 mm were prepared, including different replacement levels of fly ash (FA) in the absorbing layer as well as the matching layer for impedance matching. Waste polyethylene terephthalate bottle fragment was introduced as electromagnetic transparent reinforcement aggregate. Carbon black was used to be original absorbent in the absorbing layer. The microstructure and electromagnetic parameters of FA were closely looked at through scanning electron microscope, X-ray diffraction, and analyzer of vector network. The absorption and mechanical properties of cement-based composites were tested. It turned out that when the optimal replacement ratio of FA in the absorbing layer and matching layer gets to 50%:30%, the minimum value of reflection loss achieves −22.3 dB at 13.2 GHz; also, the value of absorption bandwidth that is effective (<−8 dB) is 6.4 GHz. Ni-Zn ferrite proves to be a feasible absorbent that is additional for the matching layer compared to what is added to the absorbing layer. The compressive strength of all the mixtures decreased, while the flexural strength decreased first and then increased with the rise of the FA replacement level.


2017 ◽  
Vol 12 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Siriporn Sirikingkaew ◽  
Nuta Supakata

This study presents the development of geopolymer bricks synthetized from industrial waste, including fly ash mixed with concrete residue containing aluminosilicate compound. The above two ingredients are mixed according to five ratios: 100:0, 95:5, 90:10, 85:15, and 80:20. The mixture's physico-mechanical properties, in terms of water absorption and the compressive strength of the geopolymer bricks, are investigated according to the TIS 168-2546 standard. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses are used to investigate the microstructure and the elemental and phase composition of the brick specimens. The results indicate that the combination of fly ash and concrete residue represents a suitable approach to brick production, as required by the TIS 168–2546 standard.


2020 ◽  
Vol 5 (2) ◽  
pp. 14
Author(s):  
Matthew S. Sullivan ◽  
Mi G. Chorzepa ◽  
Stephan A. Durham

Ternary blends of cementitious materials are investigated. A cement replacement level of 45% is used for all ternary mixtures consisting of 15% metakaolin and 30% slag replacements. Three metakaolin and two blast furnace slag, referred to as ‘slag’ for short, products commercially available are used to compare performance in ternary blends. A mixture with a 45% fly ash replacement is included to serve as a benchmark for performance. The control mixture contains 422 kg of cement per cubic meter of concrete, and a water-to-cementitious material ratio of 0.43 is used for all mixtures with varying dosages of superplasticizer to retain workability. Mixtures are tested for mechanical properties, durability, and volumetric stability. Mechanical properties include compression, split-cylinder tension, modulus of rupture, and dynamic Young’s modulus. Durability measures are comprised of rapid chloride-ion penetrability, sulfate resistance, and alkali–silica reactivity. Finally, the measure of dimensional stability is assessed by conducting drying shrinkage and coefficient of thermal expansion tests. Results indicate that ternary mixtures including metakaolin perform similarly to the control with respect to mechanical strength. It is concluded that ternary blends perform significantly better than both control and fly ash benchmark in tests measuring durability. Furthermore, shrinkage is reduced while the coefficients of thermal expansion are slightly higher than control and the benchmark.


2019 ◽  
Vol 292 ◽  
pp. 102-107 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Karel Šeps ◽  
Roman Chylík ◽  
Vladimír Hrbek

High-performance concrete is a very specific type of concrete. Its production is sensitive to both the quality of compounds used and the order of addition of particular compounds during the homogenization process. The mechanical properties were observed for four dosing procedures of each of the three tested concrete mixtures. The four dosing procedures were identical for the three mixes. The three mixes varied only in the type of supplementary cementitious material used and in water content. The water content difference was caused by variable k-value of particular additives. The water-to-binder ratio was kept constant for all the concretes. The additives used were metakaolin, fly ash and microsilica. The comparison of particular dosing procedures was carried out on the values of basic mechanical properties of concrete. The paper compares compressive strength and depth of penetration of water under pressure. Besides the comparsion of macro-mechanical properties, the effect of microsilica and fly ash additives on micro-mechanical properties was observed with the use of scanning electron microscopy (SEM) and nanoindentation data analysis. Nanoindentation was used to determine the thickness and strength of interfacial transition zone (ITZ) for different sequence of addition of cement, additive and aggregate. The thickness obtained by nanoindentation was further investigated by SEM EDS line scanning.


2012 ◽  
Vol 598 ◽  
pp. 388-392
Author(s):  
Hong Qiang Chu ◽  
Lin Hua Jiang ◽  
Ning Xu ◽  
Chuan Sheng Xiong

The mechanical properties of C100 high-strength concrete used for frozen shaft were studied in this research. The results demonstrate that: The cementitious materials 570kg/m3 concrete 28 strength is only 104.5MPa, which is lower than the C100 requirements; the early strength (3d) of the concrete doped with 30% admixture is less than 20% admixture concrete, but with the age increase, its strength gradually reaches close to concrete doped with 20% admixture, and eventually exceeds the concrete doped with 20% admixture.The tension-compression of high strength concrete doped with 15% fly ash and 15% slag is the smallest, while the tension-compression of the concrete doped 10% fly ash and 10% slag reaches the maximum.The Poisson's ratio of C100 concrete is between 0.20 and 0.24; the compressive elastic modulus is about 50GPa; and the tensile elastic modulus is about 110GPa.


2017 ◽  
Vol 116 (7) ◽  
pp. 355-361 ◽  
Author(s):  
Zaib Hussain ◽  
Rohama Maqsood ◽  
Muhammad Imran Din ◽  
Shahzad Maqsood Khan ◽  
Akhtar Shahnaz ◽  
...  

2012 ◽  
Vol 174-177 ◽  
pp. 802-805 ◽  
Author(s):  
Zhu Ding ◽  
Bi Qin Dong ◽  
Feng Xing

The accumulation of fly ash leads to severe problems in ecological environments. Various ways to excite the activity of fly ash in Portland cement based cementitious materials have been carried out for many years. In the present study, effect of large volume of fly ash in phosphate cement was studied. Dead burned magnesia, two phosphates (monoammonium phosphate and monosodium phosphate), and fly ash were used. The fabricated cement mortar specimens with different fly ash dosages were cured for 28 days in the lab air. Compressive strength was determined in 1d, 3d, 7d and 28d respectively. It is showed the compressive strength reduced with increase of fly ash content and increased with the curing time. After cured 28 days, the compressive strength of cement mortar developed to14MPa, when 80% fly ash was used. The reaction product, Na2HPO4•17H2O was found by X-ray diffraction analysis in sodium phosphate based cement. No ammonia gas was emitted and large volume of fly ash can be used in cement prepared from sodium phosphate. It is a new environmentally friendly cement material.


2008 ◽  
Vol 8 (4) ◽  
pp. 1937-1941
Author(s):  
R. Barbosa ◽  
E. M. Araújo ◽  
T. J. A. Melo ◽  
E. N. Ito ◽  
E. Hage

High density polyethylene/Brazilian clay nanocomposites were prepared by the melt intercalation technique. A montmorillonite sample from Boa Vista/PB, Northeast of Brazil, was organically modified with esthearildimethylammonium chloride (Praepagen WB) quaternary ammonium salt. The unmodified and modified clays with the quaternary ammonium salt were introduced in 1, 2, 3 and 5 wt% in a PE polymer matrix. The dispersion analysis and the interlayer distance of the clay particles were obtained by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The mechanical properties of tensile and the flammability of the nanocomposites were studied. In general, the mechanical properties of the systems presented superior values compared to the matrix. The systems showed a reduction on the burning rate, indicating that the flammability resistance of nanocomposites was improved.


2014 ◽  
Vol 548-549 ◽  
pp. 228-232 ◽  
Author(s):  
Xiao Chen ◽  
Ji Wei Liu ◽  
Ming Kai Zhou

To improve the impact of fly ash on the properties of cement-fly ash stabilized crushed stone, and promote it popularize and apply better. This paper investigated the effect of fly ash content on unconfined compressive strength, cleavage strength and resilient modulus of cement-fly ash stabilized crushed stones, and those relationships between mechanical parameters. The results showed that with increasing of the fly ash content, the unconfined compressive strength and cleavage strength increased at first, then decreased, the resilient modulus decreased, and The brittleness index increased. We can conclude that the optimal fly ash content is between 10% and 15%, and increment of fly ash content can improve its crack-resistance.


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