scholarly journals Generalized Fracture Toughness and Compressive Strength of Sustainable Concrete Including Low Calcium Fly Ash

Materials ◽  
2017 ◽  
Vol 10 (12) ◽  
pp. 1393 ◽  
Author(s):  
Grzegorz Golewski
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sustainable Concrete ◽  
Low Calcium

Compressive strength and microstructure evolution of low calcium brown coal fly ash-based geopolymer

2019 ◽  
Vol 9 (1) ◽  
pp. 17-34 ◽  
Author(s):  
Muhamed Khodr ◽  
David W. Law ◽  
Chamila Gunasekara ◽  
Sujeeva Setunge ◽  
Robert Brkljaca
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Brown Coal ◽  
Microstructure Evolution ◽  
Coal Fly Ash ◽  
Low Calcium

Experimental Study on Sustainable Concrete with the Mixture of Low Calcium Fly Ash and Lime as a Partial Replacement of Cement

2011 ◽  
Vol 250-253 ◽  
pp. 307-312 ◽  
Author(s):  
Muthuramalingam Jayakumar ◽  
M. Salman Abdullahi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Chloride Ion ◽  
Apparent Volume ◽  
Partial Replacement ◽  
Fly Ash Concrete ◽  
Low Calcium ◽  
Chloride Ion Penetration ◽  
Ion Penetration

Even though the use of fly ash in concrete is nowadays a common practice, its relatively slow pozzolanic reactivity hinders its greater utilization; hence efficient methods of activation are on demand. This study was carried out to evaluate the influence of lime as a chemical activator on the mechanical and durability properties of high strength fly ash concrete. Mixtures were made with 0, 30, 40, and 50% of cement replaced by low calcium fly ash. Corresponding mixtures were also made with the same amount of fly ash and addition of 10% of lime to each mixture. For each concrete mixture, slump, compressive strength, water absorption, sorptivity, apparent volume of permeable voids, and resistance to chloride-ion penetration were measured. The results obtained showed that addition of lime improved the compressive strength significantly at all ages. The strength of all the fly ash mixtures containing lime surpassed that of the corresponding Portland cement mix at 60 days. Addition of lime also improved the sorptivity and resistance to chloride-ion penetration of the fly ash concrete. It however increases the water absorption and the volume of permeable voids of the fly ash concrete.

Effects of Fly Ash Particle Sizes on the Compressive Strength and Fracture Toughness of High Performance Concrete

2011 ◽  
Vol 284-286 ◽  
pp. 984-988
Author(s):  
An Shun Cheng ◽  
Yue Lin Huang ◽  
Chung Ho Huang ◽  
Tsong Yen
Keyword(s):  
Fracture Toughness ◽  
Particle Size ◽  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Strength ◽  
Bending Test ◽  
Strength Development ◽  
Particle Sizes

The study aims to research the effect of the particle size of fly ash on the compressive strength and fracture toughness of high performance concrete (HPC). In all HPC mixtures, the water-to-binder ratio selected is 0.35; the cement replacement ratios includes 0%, 10% and 20%; the particle sizes of fly ash have three types of passing through sieves No. 175, No. 250 and No. 325. Three-point-bending test was adopted to measure the load-deflection relations and the maximum loads to determine the fracture energy (GF) and the critical stress intensity factor (KSIC). Test results show that adding fly ash in HPC apparently enhances the late age strengths of HPC either for replacement ratio of 10% or 20%, in which the concrete with 10% fly ash shows the higher effect. In addition, the smaller the particle size is the better the late age concrete strength will be. The HPC with the finer fly ash can have higher strength development and the values of GF and KSIC due to the facts of better filling effect and pozzolanic reaction. At late age, the GF and KSIC values of concrete with 10% fly ash are all higher than those with 20% fly ash.

scholarly journals An Experimental Study of the Effects of Low-Calcium Fly Ash on Type II Concrete

Ceramics ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 600-617
Author(s):  
Kong Fah Tee ◽  
Sayedali Mostofizadeh
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Weight Ratio ◽  
High Strength ◽  
Cementitious Materials ◽  
Alkaline Solutions ◽  
Curing Period ◽  
Low Calcium ◽  
Permeation Properties

In this study, the compressive strength and the permeation properties of fly ash-based Geopolymer were experimentally investigated. Type 2 Portland cement (T2PC) was partially or entirely replaced with 0, 10, 20, 30, 50, 70, and 100% of fly ash (FA). The laboratory tests were conducted for compressive strength at 7, 28, and 90 days, and permeation properties such as water absorption at 7 and 28 days. The main goal was to produce eco-friendly concrete with high strength and low permeability through blending cementitious materials including low Calcium (Ca) (T2PC and FA) for protecting concrete against sulphate attacks and other chemically destructive compounds in the environment. This study focused on the effectiveness of the curing period, combinations of chemical activators by varying the molarity of alkaline solutions between 4.16 and 12.96 M and keeping the sodium silicate (SS) to sodium hydroxide (SH) by the weight ratio of 2.5. Lab observations from this study demonstrated that the compressive strength was enhanced with the increment in fly ash content at all ages, with optimum being at 20% as the replacement of T2PC.

scholarly journals Fabrication and Characterization of Az91e Hybrid Metal Matrix Composites

2020 ◽  
Vol 9 (7) ◽  
pp. 163-167
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Fly Ash ◽  
Metal Matrix ◽  
Base Material ◽  
Vortex Method ◽  
Stir Casting ◽  
Equal Weight ◽  
Matrix Composites ◽  
Component Technique

The current work expects to decide the attributes of compression of the (Magnesium composite) AZ 91E-Zro2-Fly Ash Hybrid Metal Matrix utilizing the conventional explanatory strategy and limited component technique. Fly ash and ZrO2 taken as equal weight proportions, composites are fabricated by means of a vortex method under the path of stir casting. The density and fracture toughness were found experimentally, the experimental density was decreased compare to the theoretical density, but the density is increased slightly for composites compare to the base material. The fracture toughness is decreased for composites compare to the base material; this is due to the improvement of the grains by adding strengthening molecules. The compressive strength was decreased by decreasing of the height of the deformation in percentage for base material and the composites of H/D 1.0 and 1.5. The compressive strength is high for the composites compare to the base material even the density of the composite is little bit high, hence suggested that composite system gives the better compressive strength results

Zeta potential, gel formation and compressive strength of low calcium fly ash geopolymers

2015 ◽  
Vol 95 ◽  
pp. 592-599 ◽  
Author(s):  
Chamila Gunasekara ◽  
David W. Law ◽  
Sujeeva Setunge ◽  
Jay G. Sanjayan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Zeta Potential ◽  
Gel Formation ◽  
Low Calcium

Improving compressive strength of low calcium fly ash geopolymer concrete with alccofine

2017 ◽  
Vol 5 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Bharat Bhushan Jindal ◽  
Dhirendra Singhal ◽  
Sanjay K. Sharma ◽  
Deepankar K. Ashish ◽  
Parveen Parveen
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Geopolymer Concrete ◽  
Low Calcium

scholarly journals Mechanical and microstructural characterization of geopolymer synthesized from low calcium fly ash

2015 ◽  
Vol 21 (1-1) ◽  
pp. 13-22 ◽  
Author(s):  
Sabina Kramar ◽  
Vilma Ducman
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Content ◽  
Sodium Silicate Solution ◽  
Microstructural Characterization ◽  
Silicate Solution ◽  
Low Calcium ◽  
Pore Size Distributions ◽  
Compressive Tests

This study deals with the mechanical and microstructural characterization of geopolymers synthesized from locally available fly ash. A low calcium fly ash was activated using a sodium silicate solution. Samples were characterized by means of flexural and compressive tests, Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). Porosity and pore size distributions were identified using mercury intrusion porosimetry and gas sorption. The compressive strength of the produced geopolymers, which is in the range of 1.6 to 53.3 N/mm2, is strongly related to the water content as well as SiO2/Na2O mass ratio of an alkali activator. The compressive strength significantly increased with decreases in the water content and increased silicon concentration used for the synthesis of geopolymers.

scholarly journals Changes in the Fracture Toughness under Mode II Loading of Low Calcium Fly Ash (LCFA) Concrete Depending on Ages

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5241 ◽  
Author(s):  
Grzegorz Ludwik Golewski
Keyword(s):  
Fracture Toughness ◽  
Fly Ash ◽  
Mode Ii ◽  
Test Results ◽  
Shear Loads ◽  
Concrete Mixtures ◽  
Low Calcium ◽  
Plastic Process ◽  
Mode Ii Loading ◽  
Different Content

This study investigated the influence of the curing time on the fracture toughness of concrete produced with different content of low calcium fly ash (LCFA). During the study, the amounts of 20% and 30% of pozzolanic additive were used. In order to observe the effect of the applied pozzolanic additive on the analyzed concrete properties, the obtained results were compared with the values obtained for the reference concrete. Compressive strength—fcm and fracture toughness, by using mode II loading—KIIc (shearing), were determined between the 3rd and 365th days of curing. In the course of experiments, changes in the development of cracks in individual series of concrete were also analyzed. In addition, the microstructures of all composites and the nature of macroscopic crack propagation in mature concretes were assessed. It was observed that the greatest increase in fracture toughness at shear was in the case of reference concrete during the first 28 days, whereas, in the case of concretes containing LCFA, in the period of time above 4 weeks. Furthermore, concrete without the LCFA additives were characterized by a brittle fracture. In contrast to it, concretes with LCFA additives are mainly characterized by a quasi-plastic process of failure. Moreover, most of the samples showed a typical pattern of the destruction that occurs as a result of shearing. The presented test results may be helpful in selecting the composition of concrete mixtures containing LCFA to be used in concrete and reinforced concrete structures subjected to shear loads.

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