scholarly journals Feasibility of Pulverized Oyster Shell as a Cementing Material

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Chou-Fu Liang ◽  
Hung-Yu Wang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Oyster Shell ◽  
Pozzolanic Reaction ◽  
Compaction Process ◽  
Lower Strength ◽  
Compacted Soil ◽  
Cementing Material ◽  
Unconfined Strength ◽  
Strength Variance

This research intends to study the cementing potential of pulverized oyster shell, rich in calcium, when mixed with fly ash and soil. Cylindrical compacted soil and cubic lime specimens with different proportions of the shells and fly ash are made to study the strength variance. Soil, which is classified as CL in the USCS system, commercialized pulverized oyster shell, F-type fly ash, and lime are mixed in different weight percentages. Five sample groups are made to study the compressive strength of soil and lime specimens, respectively. The lime cubes are made with 0.45 W/B ratio and the cylindrical soils are compacted under the standard Procter compaction process with 20% moisture content. The results show that increment of shell quantity result to lower strength on both the soil and lime specimens. In a 56-day curing, the compressive strength of the lime cubes containing fly ash increases evidently while those carrying the shell get little progress in strength. The soil specimens containing fly ash gradually gain strength as curing proceeds. It suggests that mixtures of the shell and fly ash do not process any Pozzolanic reaction nor help to raise the unconfined strength of the compacted soil through the curing.

scholarly journals Thermal, Physico-Chemical, and Mechanical Behaviour of Mass Concrete with Hybrid Blends of Bentonite and Fly Ash

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 60 ◽  
Author(s):  
Muhammad Ahad ◽  
Muhammad Ashraf ◽  
Rabinder Kumar ◽  
Mukhtar Ullah
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Thermal Stresses ◽  
Thermo Gravimetric Analysis ◽  
Xrd Analysis ◽  
Pozzolanic Reaction ◽  
Pulse Velocity ◽  
Mass Concrete ◽  
Gravimetric Analysis ◽  
Physico Chemical

Mass concrete has been commonly known for its thermal stresses which arise due to the entrapment of hydration temperature susceptible to thermal cracking. The utilization of mineral additives is a promising and widely adopted technique to mitigate such effects. This paper presents the thermal, physico-chemical, mechanical, and morphological behaviour of mass concrete with blends of bentonite (BT) and fly ash (FA). Apart from the rise in temperature due to hydration, the compressive strength, ultrasonic pulse velocity (UPV), differential thermal analysis (DTA), thermo-gravimetric analysis (TGA), X-ray diffraction (XRD) analysis, and microstructure were studied. The results of this study revealed that the substitution of BT and FA significantly improved the compressive strength and development rate of UPV in the mass concrete samples. The FA concrete (FC) specimen presented the lowest temperature during the peak hours compared to all other concrete mixes studied in this research. Bentonite concrete (BC) was also found to be more effective in controlling the escalation of temperature in mass concrete. Scan electron microscopy (SEM) micrographs presented partially reacted FA particles in a mix. XRD and DTA analysis indicated that the concentration of calcium hydroxide (CH) declined by substituting FA and BT, specifically in ternary blends, which was due to the dilution effect and consumption of CH through the pozzolanic reaction.

Effect of Alkaline Solution to Fly Ash Ratio on Geopolymer Mortar Properties

2017 ◽  
Vol 733 ◽  
pp. 85-88 ◽  
Author(s):  
Amir Fauzi ◽  
Mohd Fadhil Nuruddin ◽  
Ahmad B. Malkawi ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Bashar S. Mohammed
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Alkaline Solution ◽  
Similar Pattern ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Pozzolanic Reaction

Geopolymer system is new binding materials in concrete industry that is produced by the alkaline solution and materials rich in aluminosilicate such as fly ash. The effect of the alkaline solution to fly ash ratios of 0.3, 0.4 and 0.5 on mortar geopolymer properties was an issue in this study. The results showed that the higher alkaline solution to fly ash ratio improves the workability and brings a longer setting time, whereas the lower alkaline solution to fly ash ratio gains the significant compressive strength. It was a similar pattern with conventional mortar used ordinary Portland cement, which the compressive strength at 7 days was 85%-90% for 28 days compressive strength, whereas conventional mortar is only 65%-75%. This was due to the higher reactivity in geopolymer system that was faster than the pozzolanic reaction.

Influences of Slag and Fly Ash on the Microstructure Property and Compressive Strength of Concrete

2010 ◽  
Vol 146-147 ◽  
pp. 1690-1697 ◽  
Author(s):  
An Shun Cheng ◽  
Chung Ho Huang ◽  
Tsong Yen ◽  
Yong Lin Luo
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Pore Volume ◽  
Total Pore Volume ◽  
Pozzolanic Reaction ◽  
Test Results ◽  
Suitable Amount ◽  
Pozzolanic Materials ◽  
Microstructure And Mechanical Property ◽  
Better Than

This research aims to investigate the pore structures and the interfacial transition zone (ITZ) of concrete containing both slag and fly ash. Test variables include three water-to-binder ratios (0.35, 0.50, 0.70) and four substitute ratios of cement with pozzolanic materials (20%, 30%, 50% and 60%). The specimens were tested to determine compressive strength, MIP porosity measurement and ITZ microhardness. Test results show that concrete containing slag and fly ash produce evident filling effect and the pozzolanic reaction after 28 days. At the age of 91 days the pozzolanic materials has provided prominent contribution to the strength, the porosity and the ITZ of concrete, making the pore volume smaller and ITZ property of pozzolanic concrete better than that of normal concrete. The concrete that adds suitable amount of pozzolanic materials (ex. 10% slag + 10% fly ash) has the optimum microstructure and mechanical property. Too much pozzolanic materials (ex. 40% slag + 20% fly ash) may be disadvantage to the concrete, and the suggested substitute ratio is under 50%. It is found that the compressive strength has the closest relationship with the total pore volume, so we use the total pore volume to predict the compressive strength of pozzolanic concrete and establish a prediction model as follow: S= -662.68Vt+87.29, R2=0.946.

Comparison of innovative nano fly ash with conventional fly ash and nano-silica

2014 ◽  
Vol 41 (5) ◽  
pp. 396-402 ◽  
Author(s):  
Seong-Soo Kim ◽  
R. Doug Hooton ◽  
Tae-Jun Cho ◽  
Jeong-Bae Lee
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Physical Method ◽  
Pozzolanic Reaction ◽  
Superior Performance ◽  
Particle Sizes ◽  
Nano Silica ◽  
Initial Strength ◽  
Carbonation Resistance ◽  
Chloride Penetration Resistance

This report is an experimental study on the nano-powdering of fly ash and the improvement of cement performance by nano fly ash. Mortars with nano fly ash or nano-silica produced by a physical method are compared with mortar without a nano-binder. Mortar with nano-silica showed rapid setting. However, mortar with fly ash or nano fly ash exhibited delayed setting. The smaller the particle sizes, the higher is the compressive strength, demonstrating that mortar with nano fly ash shows superior performance with higher compressive strength from the beginning. Durability assessments revealed that chloride penetration resistance increased by 70% for mortar with nano fly ash or nano-silica. This shows that mortar with a smaller particle binder has excellent carbonation resistance. Nano-powdering effectively enhances the activation of a pozzolanic reaction and provides densely charged effects. These changes solve the problem of initial strength reduction — the greatest weakness of fly ash.

scholarly journals USE OF FINE GROUND DUNE SAND AS A SUPPLEMENTARY CEMENTING MATERIAL

2014 ◽  
Vol 20 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Abdulrahman Alhozaimy ◽  
Omer Abdalla Alawad ◽  
Mohd Saleh Jaafar ◽  
Abdulaziz Al-Negheimish ◽  
Jamaloddin Noorzaei
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Calcium Hydroxide ◽  
Pozzolanic Reaction ◽  
Dune Sand ◽  
Cement Production ◽  
Curing Conditions ◽  
High Consumption ◽  
Autoclave Curing ◽  
Cementing Material

The process of Portland cement production is associated with high consumption of energy and resources. Therefore, there is a need to replace the Portland cement with environmental friendly materials. This study was conducted to determine the feasibility of using ground dune sand as cement replacement materials under different curing conditions. Portland cement was replaced by ground dune sand at five levels of replacement (0–40% by weight). The compressive strength of mortar under standard and autoclave curing conditions and the influence of different autoclave temperatures and durations were investigated. The microstructure of selected mixtures was analyzed by XRD and SEM. Results showed that the compressive strength under the standard curing decreased as the level of replacement increased. However, under autoclave curing compressive strength increased as the content of ground dune sand increased. XRD and SEM revealed the absence of calcium hydroxide and the formation of secondary calcium silicate hydrate. The improvement of compressive strength and the absence of calcium hydroxide under autoclave curing indicated that the pozzolanic reaction between silica of dune sand and calcium hydroxide occurred.

scholarly journals Performance of Fly Ash Bricks with Differential Composition

2019 ◽  
Vol 9 (1) ◽  
pp. 4550-4556
Keyword(s):  
Experimental Investigation ◽  
Compressive Strength ◽  
Fly Ash ◽  
Construction Industry ◽  
Silica Fume ◽  
Cement Content ◽  
Maximum Strength ◽  
Manufacturing Plant ◽  
Lower Strength

Flyash is one of the largest emerging products in the construction industry. The fly ash is the by-product which is widely used in brick manufacturing plant. The flyash reduces the cement content and also overcomes several disadvantages. Simply, it is a step towards eco-friendly environment. Though the flyash brick has many advantages, it has lower strength at initial stages due to low hydration. In this study, the experimental investigation was carried out to find the optimum mix ratio of various compositions of fly ash bricks. The brick specimens were casted on different compositions of cement, flyash, eco-sand and various other admixtures. On addition of these admixtures the early compressive strength was also high and a quick hydration was observed. The tests were conducted on 3rd, 5th, 7th and 28th day. The results suggest that the maximum strength was obtained for the composition of fly ash, ecosand, cement and silica fume.

Hydroceramic-Concrete Designed for a Project Material of Soil Stabilization

2012 ◽  
Vol 450-451 ◽  
pp. 756-763
Author(s):  
Ri Gao Chen ◽  
Yi Lan Chen ◽  
Xin Yue Zhao ◽  
Michael W Grutzeck
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Room Temperature ◽  
Soil Stabilization ◽  
Coagulation Time ◽  
Conventional Concrete ◽  
Good For ◽  
Class F Fly Ash ◽  
Cementing Material ◽  
Class F

As the traditional material commonly used, cement has its own limitation such as limited solidifying objects, bad stability in water, high cost and uneasy adjustment in coagulation time, not good for solidifying the waste etc.. The succeed in developing a hydroceramic-concrete for soil stabilization can take place of traditional cementing material such as conventional concrete applying and avoid the shortage of them. Here we show that a mixture of Class F fly ash, metakaolin and 8M NaOH (hydroceramic) will harden at room temperature, attaining 9.2 MPa compressive strength at 90 days, It is suggested that a hydroceramic-concrete may be used as a project material of soil stabilization as it has similar or even better compressive strength than conventional concrete.

scholarly journals Self-Consolidating Lightweight Concrete Incorporating Limestone Powder and Fly Ash as Supplementary Cementing Material

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3050 ◽  
Author(s):  
Khan ◽  
Usman ◽  
Rizwan ◽  
Hanif
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Limestone Powder ◽  
Normal Weight Concrete ◽  
Supplementary Cementing Materials ◽  
Fresh State ◽  
Cementing Material

This paper assesses the mechanical and structural behavior of self-consolidating lightweight concrete (SCLWC) incorporating bloated shale aggregate (BSA). BSA was manufactured by expanding shale pellets of varying sizes by heating them up to a temperature of 1200 °C using natural gas as fuel in the rotary kiln. Fly ash (FA) and limestone powder (LSP) were used as supplementary cementing materials (10% replacement of cement, each for LSP and FA) for improved properties of the resulting concrete. The main parameters studied in this experimental study were compressive strength, elastic modulus, and microstructure. The fresh-state properties (Slump flow, V-funnel, J-Ring, and L-box) showed adequate rheological behavior of SCLWC in comparison with self-consolidating normal weight concrete (SCNWC). There was meager (2%–4%) compressive strength reduction of SCLWC. Lightweight aggregate tended to shift concrete behavior from ductile to brittle, causing reduced strain capacity and flexural toughness. FA and LSP addition significantly improved the strength and microstructure at all ages. The study is encouraging for the structural use of lightweight concrete, which could reduce the overall construction cost.

scholarly journals Experimental Study on Mechanical Properties of Fly Ash Stabilized with Cement

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Shengquan Zhou ◽  
Yongfei Zhang ◽  
Dawei Zhou ◽  
Weijian Wang ◽  
Dongwei Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Early Stage ◽  
Strain Curve ◽  
Pozzolanic Reaction ◽  
Hydration Reaction ◽  
Hydration Products ◽  
Compressive Test ◽  
Plastic Properties

Cement-fly ash mixture has been commonly used for the foundation treatment projects in the fly ash stratum, as it is effective in improving foundation bearing capacity and reducing settlement of stratum. In order to figure out the effect of dynamic and static load on the mechanical properties exhibited by the cement-fly ash and the reaction mechanism of cement-fly ash, a combination of the unconfined compressive test, impact test, scanning electron microscopy (SEM), and X-ray diffraction (XRD) method was adopted in this study to investigate the cement-fly ash test samples. As demonstrated by the results, the observed growth rate of 0–60 days (d) is higher than that in the later stages and the typical stress-strain curve can be divided into six sections under the unconfined compressive test. At the gas pressure of 0.2 MPa, the cement-fly ash samples exhibited obvious plastic properties in early curing time (0–60 d), and brittle failure was observed in the final stage (90 d). It is obvious that the value of dynamic compressive strength (DCS) is higher than that of unconfined compressive strength (UCS). The analysis of XRD has revealed that the hydration products are primarily derived from the hydration reaction of cement in the early stage and the pozzolanic reaction in the late stage. The pores of cement-fly ash are found to be filled with the hydration products, despite the presence of a mass of pores in the interior.

Analysis of the Cementitious and Pozzolanic Properties of a Silico-Aluminous (Class F) Fly Ash

1985 ◽  
Vol 65 ◽  
Author(s):  
Andre Carles-Gibergues ◽  
Pierre-Claude Aitcin
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Chemical Composition ◽  
Pure Water ◽  
Mineralogical Composition ◽  
Pozzolanic Reaction ◽  
Strength Increase ◽  
Lime Water ◽  
Physico Chemical ◽  
Class F

ABSTRACTA silico-aluminous (Class F) French fly ash has been studied during the last ten years. While over this period the fly ash was produced from different bituminous coals, it has demonstrated high constancy in terms of its chemical and physical composition as well as cementitious properties. The first part of this paper gives a complete physico-chemical characterization of this fly ash, including chemical composition, mineralogical composition of its crystallized fraction, chemical composition of its glass, grain-size distribution, specific surface area, and bulk density. The second part deals with physico-chemical experiments performed to determine the cementitious components of this fly ash through its dissolution in pure water and in lime water. The lime water experiment was also carried out on a washed sample containing few residual sulfates. This series of experiments demonstrates the importance of sulfates in this particular fly ash, especially during the early stages of hydration. Their action results in the formation of ettringite. The cementitious role of these sulfates has been confirmed by comparing the compressive strength of mortar cubes containing washed and nonwashed fly ash. After 7 days, mortar cubes made with this fly ash showed a slight compressive strength increase when compared to a reference mix containing the same amount of quartz. This compressive strength increase can be related to the formation of C-S-H due to the pozzolanic reaction. After 8 months, the pozzolanic reaction had consumed most of the lime generated by the hydration of C2S and C3S, so that practically no portlandite remained in the mortar.

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