scholarly journals Compression Characteristics and Microscopic Mechanism of Coastal Soil Modified with Cement and Fly Ash

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3182 ◽  
Author(s):  
Na Li ◽  
Qianying Zhu ◽  
Wei Wang ◽  
Fei Song ◽  
Dongliang An ◽  
...  

It is of great significance to study the consolidation characteristics of modified coastal cement-soil. A one-dimensional consolidation test and microscopic test were carried out. In the tests, the cement content was 20%, fly ash content was 0%, 5%, 10%, 20%, and 30%, and the water content was 80%. The consolidation test results showed that: (1) Compared with coastal cement soil, the deformation of coastal cement soil modified with a 20% fly ash content was reduced from 4.31 to 2.70 mm, and the vertical compression deformation was reduced by 1.61 mm. (2) During consolidation and compression, the e–p curve (pore ratio-pressure curve) of fly ash-modified coastal cement soil was slower than that of coastal cement soil and the rate of change of pore ratio. (3) The compression coefficient of fly ash-modified coastal cement soil was reduced from 0.780 to 0.598 MPa-1 compared with that of coastal cement soil. The microscopic test results indicate that after adding the proper amount of fly ash, a skeleton was formed between the microscopic particles of the sample, which improved its resistance to compression and deformation. The results of this study indicate that it is feasible to modify coastal cement soil with an appropriate amount of fly ash to improve its compression resistance.

2015 ◽  
Vol 804 ◽  
pp. 129-132
Author(s):  
Sumrerng Rukzon ◽  
Prinya Chindaprasirt

This research studies the potential for using waste ash from industrial and agricultural by-products as a pozzolanic material. Classified fly ash (FA) and ground rice husk ash (RA) were the materials used. Water requirement, compressive strength and porosity of cement mortar were investigated. Test results indicated that FA and RA (waste ash) have a high potential to be used as a good pozzolanic material. The water requirement of mortar mix decreases with the increases in fly ash content. For ground rice husk ash (RA), the water requirement of mortar mix increases with the increases in rice husk ash content. In addition, the reduction in porosity was associated with the increase in compressive strength.


2015 ◽  
Vol 789-790 ◽  
pp. 38-42
Author(s):  
Nuria S. Mohammed ◽  
Ahmed Baharuddin Abd Rahman ◽  
Nur Hafizah A. Khalid ◽  
Musaab Ahmed

Polymer resin grout can be used as bonding material for grouted sleeve connections This paper presents the experimental results on the effectiveness of fly ash as micro filler to the splitting tensile strength of polymer grout. In addition, the cement grout that is usually used as bonding material had been tested for comparison. Eleven proportions, of fly ash as the filler and polymer as binder, were tested with the binder to filler volume ratios of 1:1 and 1:1.5. The test results revealed that fly ash can be used as a micro-filler material to partially replace ordinary river sand in polymer resin grout. The splitting tensile strength of the polymer grout increases with the increase of fly ash contents. However, for higher level of fly ash of more than 22%, the splitting tensile strength deteriorated. For binder: filler ratio of 1:1, the optimum fly ash content of 22% gave the maximum splitting strength of 17.62 MPa, which can be considered acceptable for producing grout with high strength bonding material.


2013 ◽  
Vol 357-360 ◽  
pp. 671-675
Author(s):  
Zhong Dong Liu ◽  
Wen Juan Zhao

In this paper the molding mechanisms of mibration compaction for concrete bricks is explained. A lot of concrete bricks with different ash content were by a vibration compaction machines produced. The characteristics of the concrete bricks are investigated. The experiments showed that the starting hardness of the concrete bricks at the separation from molding tools is sufficient for brick stacking.


2012 ◽  
Vol 238 ◽  
pp. 138-141
Author(s):  
Wei Xie ◽  
Hai Juan Zhang ◽  
Shu Shan Li

By the test study of basic mechanics properties of concrete with different fly ash content, the influence of the content of fly ash on the compressive strength, flexural strength, splitting tensile strength and static compressive elastic modulus of concrete are analyzed with the explaining of the influence mechanism of fly ash. The test results show that, comparing with the normal reference concrete, the early age strength of fly ash concrete enhances slowly, while the late strength develops rapidly, even overpasses the strength of normal reference concrete.


2018 ◽  
Vol 69 (8) ◽  
pp. 2040-2044
Author(s):  
Georgeta Velciu ◽  
Virgil Marinescu ◽  
Adriana Moanta ◽  
Ladislau Radermacher ◽  
Adriana Mariana Bors

The influence of fly ash adittion (90 % fraction [ 100 mm) on the cement mortar characteristics was studied. The XRD, XRF, SEM and FTIR determinations indicated that fly ash used has a hollow microstructure of microsphere and cenosphere whose total content in SiO2, Al2O3 and Fe2O3 is 88.63 % and that of CaO and MgO of 8.55 %. The mechanical, thermal and dielectric determinations made on mortar samples with content of fly ash in the 0-40 % range have highlighted fact that the mechanical strength of cement mortars is maximal at 20 %, the increase in fly ash content leads to a decrease in relative density and thermal conductivity as well as and to increased dielectric losses tgd.


Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 875
Author(s):  
Chenchen Luan ◽  
Qingyuan Wang ◽  
Fuhua Yang ◽  
Kuanyu Zhang ◽  
Nodir Utashev ◽  
...  

There have been a few attempts to develop prediction models of splitting tensile strength and reinforcement-concrete bond strength of FAGC (low-calcium fly ash geopolymer concrete), however, no model can be used as a design equation. Therefore, this paper aimed to provide practical prediction models. Using 115 test results for splitting tensile strength and 147 test results for bond strength from experiments and previous literature, considering the effect of size and shape on strength and structural factors on bond strength, this paper developed and verified updated prediction models and the 90% prediction intervals by regression analysis. The models can be used as design equations and applied for estimating the cracking behaviors and calculating the design anchorage length of reinforced FAGC beams. The strength models of PCC (Portland cement concrete) overestimate the splitting tensile strength and reinforcement-concrete bond strength of FAGC, so PCC’s models are not recommended as the design equations.


2021 ◽  
Vol 11 (3) ◽  
pp. 1037
Author(s):  
Se-Jin Choi ◽  
Ji-Hwan Kim ◽  
Sung-Ho Bae ◽  
Tae-Gue Oh

In recent years, efforts to reduce greenhouse gas emissions have continued worldwide. In the construction industry, a large amount of CO2 is generated during the production of Portland cement, and various studies are being conducted to reduce the amount of cement and enable the use of cement substitutes. Ferronickel slag is a by-product generated by melting materials such as nickel ore and bituminous coal, which are used as raw materials to produce ferronickel at high temperatures. In this study, we investigated the fluidity, microhydration heat, compressive strength, drying shrinkage, and carbonation characteristics of a ternary cement mortar including ferronickel-slag powder and fly ash. According to the test results, the microhydration heat of the FA20FN00 sample was slightly higher than that of the FA00FN20 sample. The 28-day compressive strength of the FA20FN00 mix was approximately 39.6 MPa, which was higher than that of the other samples, whereas the compressive strength of the FA05FN15 mix including 15% of ferronickel-slag powder was approximately 11.6% lower than that of the FA20FN00 mix. The drying shrinkage of the FA20FN00 sample without ferronickel-slag powder was the highest after 56 days, whereas the FA00FN20 sample without fly ash showed the lowest shrinkage compared to the other mixes.


2016 ◽  
Vol 866 ◽  
pp. 99-105 ◽  
Author(s):  
Smita Singh ◽  
M.U. Aswath ◽  
R.V. Ranganath

The present investigation is on the effect of red mud on the mechanical properties and durability of the geopolymer paste in sulphuric and acetic acid solution. Red mud and fly ash were used to form the geopolymer paste along with the alkalies. The variation of red mud in the paste composition was from 0% to 90%. Cylindrical shaped specimens of 1 inch diameter and 1 inch height were prepared. The specimens were immersed in 5% sulphuric acid and 5% acetic acid for 1, 7, 14, 28, 56 and 84 days and tested for weight loss, visual deformation, strength loss and colour of the solvent, based on the procedure specified by ASTM C 267 – 01. SEM/EDX Tests were performed on the geopolymer specimens. Test results show that initially, the strength of the geopolymer increased upon the addition of red mud. The strength was maximum when the percentage of red mud was 30%. The maximum strength obtained was 38 MPa for the paste containing 30% red mud using 10M alkali solution as against 31.69 MPa, when only fly ash was used. Geopolymer paste containing 30% and 50% red mud showed better resistance to acid attack. The strength loss was minimum for the samples containing 30% red mud in both inorganic and organic acid i.e. sulphuric and acetic acid.


2011 ◽  
Vol 383-390 ◽  
pp. 3799-3804
Author(s):  
Xiao Xu Fan ◽  
Lei Zhe Chu ◽  
Li Guo Yang

The fuel characteristics of municipal sewage sludge are suitable for dual fluidized bed(DFB) gasification, which can get middle calorific value gas through volatile pyrolysis, and reduce volume through char combustion. The hot test results of municipal sewage sludge on DFB rig were showen that the temperature distribution along combustor heigh is uniform, and the carbon content of fly ash is about 2~3%. In the experiment, with the increase of gasifier temperatrue, the more volatile of the sewage sludge was pyrolyzed. When the temperature of the gasifier reached 800°C, the calorific value of gas was 6.9MJ/Nm3; the emissions of SO2, NOx and HCl were appropriate to the standard. The leaching toxicity of heavy metal of the fly ash was lower than the discharge standard.


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