scholarly journals The Influence of Ground Fly Ash on Cement Hydration and Mechanical Property of Mortar

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Jingjing Feng ◽  
Jianwei Sun ◽  
Peiyu Yan
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Pore Structure ◽  
Cement Hydration ◽  
Pozzolanic Reaction ◽  
20 Nm ◽  
Reaction Degree ◽  
Better Than

In this study, the ground fly ash is made of ordinary grade I fly ash by grinding. Compared with grade I fly ash, the influence of ground fly ash on cement hydration and mechanical property of mortar was investigated. The results show that ground fly ash can improve the hydration of cement at all the ages compared with grade I fly ash, and not only does its pozzolanic reaction start earlier, but the reaction degree is higher and the speed is quicker. Before 3 days, the contribution of ground fly ash to the strength is mainly due to physical filling and microaggregate effect. After that, the contribution of pozzolanic effect to the strength becomes obvious and can significantly increase the compressive strength after 60 days and the flexural strength after 28 days. The ground fly ash is better than grade I fly ash to optimize the pore structure of hardened pastes. It can significantly reduce the number of harmful pores (>20 nm) and increase the number of harmless pores (<20 nm), which refines the pore structure and makes the structure denser.

scholarly journals Effect of Nanosilica on Impermeability of Cement-Fly Ash System

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Huaqing Liu ◽  
Yan Zhang ◽  
Ruiming Tong ◽  
Zhaoqing Zhu ◽  
Yang Lv
Keyword(s):  
Fractal Dimension ◽  
Fly Ash ◽  
Bond Strength ◽  
Pore Structure ◽  
Calcium Hydroxide ◽  
Cement Hydration ◽  
Pozzolanic Reaction ◽  
Surface Protection ◽  
Durability Of Concrete

Surface protection has been accepted as an effective way to improve the durability of concrete. In this study, nanosilica (NS) was used to improve the impermeability of cement-fly ash system and this kind of material was expected to be applied as surface protection material (SPM) for concrete. Binders composed of 70% cement and 30% fly ash (FA) were designed and nanosilica (NS, 0–4% of the binder) was added. Pore structure of the paste samples was evaluated by MIP and the fractal dimension of the pore structure was also discussed. Hydrates were investigated by XRD, SEM, and TG; the microstructure of hydrates was analyzed with SEM-EDS. The results showed that in the C-FA-NS system, NS accelerated the whole hydration of the cement-FA system. Cement hydration was accelerated by adding NS, and probably, the pozzolanic reaction of FA was slightly hastened because NS not only consumed calcium hydroxide by the pozzolanic reaction to induce the cement hydration but also acted as nucleation seed to induce the formation of C-S-H gel. NS obviously refined the pore structure, increased the complexity of the pore structure, and improved the microstructure, thereby significantly improving the impermeability of the cement-FA system. This kind of materials would be expected to be used as SPM; the interface performance between SPM and matrix, such as shrinkage and bond strength, and how to cast it onto the surface of matrix should be carefully considered.

Research on Mechanical Property of Fiber-Reinforced Geopolymer

2012 ◽  
Vol 174-177 ◽  
pp. 757-760
Author(s):  
Qing Wang ◽  
Zhao Yang Ding ◽  
Jing Da ◽  
Zhi Tong Sui
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Polyvinyl Alcohol ◽  
Fiber Reinforced ◽  
Synthetic Fibers ◽  
Fiber Materials ◽  
Reinforcing Fiber ◽  
Better Than

The compatibility and mechanical property of two kinds of synthetic fibers to geopolymer were studied. Polyvinyl alcohol (PVA) and polypropylene (PP) were used as reinforcing fiber materials. The result shows that flexural strength of geopolymer is obviously increased by mixed with reinforcing fiber. PVA is better than PP in reinforcing the flexural strength, both of these fibers have no significant effect in reinforcing the compressive strength to geopolymer.

Influence of Variable Temperature Curing on Mechanical Properties of Fly Ash Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 178-181
Author(s):  
Ya Ding Zhao ◽  
Xue Ying Li ◽  
Ling Chao Kong ◽  
Wei Du
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Variable Temperature ◽  
Improve Performance ◽  
Curing Conditions ◽  
Fly Ash Concrete ◽  
Better Than

Under variable temperature curing conditions(30 oC ~70 oC), concrete with fly ash whose compressive strength, flexural strength, and dynamic elastic modulus are better than ones without fly ash.Compared with constant temperature 20oC, 50 oC and 70 oC, variable temperature curing(VTC) is benefit for the improvement of mechanical properties of 30% fly ash concrete, but which is no advantage to improve performance of 50% fly ash concrete.

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.

Study on Ultra-Strength Mortar Prepared with Mineral Admixture

2011 ◽  
Vol 675-677 ◽  
pp. 1073-1076
Author(s):  
Zu Quan Jin ◽  
Peng Zhang ◽  
Tie Jun Zhao ◽  
Bao Rong Hou
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Pore Structure ◽  
Silica Fume ◽  
Mineral Admixture ◽  
Replacement Rate ◽  
River Sand ◽  
Optimum Proportion ◽  
Curing Age

In this paper, preparation, property study of ultra-strength mortars with mineral admixture and clear river sand was carried out. The mineral admixture include fly ash, ultra-fine GGBS and silica fume. The experimental results show that the compressive strength of mortar improves with increasing amount of silica fume or ultra-fine GGBS. When the content of silica fume or ultra-fine GGBS is 30~35%, the compressive strength and flexural strength of mortar in curing age of 7 days are 100 MPa and 20MPa, respectively. But strength of mortar decreases with the increase replacement rate of fly ash. When the mortar mixes with combined of silica fume and ultra-fine GGBS, the optimum proportion of siliaca fume to ultra-fine GGBS is 2:3. And the compressive strength of mortar in curing age of 7 days is 75~100MPa when the mixed mineral admixture is 40~60%. The compressive strength of mortar is about 90MPa as it mix 60% of cement, 15% of silica fume, 15% of GGBS and 10% of fly ash. Moreover, the ultra strength mortar refines its pore structure and its capiliary pore (≥100nm) amount reduces by 78% compared to ordinary mortar.

Durability of Concrete Containing Wollastonite and Fly Ash

2013 ◽  
Vol 800 ◽  
pp. 361-364
Author(s):  
Lin Chun Zhang
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Modulus Of Elasticity ◽  
Dynamic Elastic Modulus ◽  
Concrete Quality ◽  
Series Of Experiments ◽  
Durability Performance ◽  
Better Than

A series of experiments were carried out to investigate the effect of wollastonite and fly ash combination on the compressive strength, flexural strength, modulus of elasticity, coming off amount, loss percentage of dynamic elastic modulus as well as surface scaling of concrete. The studies show that the effect of mixing wollastonite and fly ash can reach excellent mechanical and durability performance. The effect of mixing wollastonite and fly ash improve the mechanical and durability is better than mixing fly ash alone. The concrete mixes containing wollastonite and fly ash indicated that wollastonite addition 15% was found advantageous in improving concrete quality.

Effects of Rubber Powder and Fly Ash on Mechanical Properties of Recycled Mortars

2013 ◽  
Vol 539 ◽  
pp. 70-74
Author(s):  
Yun Fang Meng ◽  
Yong Qi Wei ◽  
De Zhi Wang ◽  
Ke Gao
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Experimental Results ◽  
Rubber Powder ◽  
Single Addition ◽  
Better Than

The effects of rubber powder (RP) and fly ash (FA) with various dosages on flexural and compressive strength of recycled mortars were investigated. Experimental results indicated that the single addition of 4 wt.% RP helped to improve the flexural strength of recycled mortars, but the compound addition of RP and FA in recycled mortars reduced the strength, whatever the compressive or flexural strength; the mechanical properties of recycled mortars with or without RP or FA were better than that of ordinary mortars.

scholarly journals Effect of Morphologically Controlled Hematite Nanoparticles on the Properties of Fly Ash Blended Cement

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1003
Author(s):  
Pantharee Kongsat ◽  
Sakprayut Sinthupinyo ◽  
Edgar A. O’Rear ◽  
Thirawudh Pongprayoon
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Size Distribution ◽  
Cement Hydration ◽  
Blended Cement ◽  
Spherical Shape ◽  
Particle Sizes ◽  
Fe2o3 Nanoparticles ◽  
Structure And Properties ◽  
Hematite Nanoparticles

Several types of hematite nanoparticles (α-Fe2O3) have been investigated for their effects on the structure and properties of fly ash (FA) blended cement. All synthesized nanoparticles were found to be of spherical shape, but of different particle sizes ranging from 10 to 195 nm depending on the surfactant used in their preparation. The cement hydration with time showed 1.0% α-Fe2O3 nanoparticles are effective accelerators for FA blended cement. Moreover, adding α-Fe2O3 nanoparticles in FA blended cement enhanced the compressive strength and workability of cement. Nanoparticle size and size distribution were important for optimal filling of various size of pores within the cement structure.

scholarly journals Assessment of the Rheological and Mechanical Properties of Geopolymer Concrete Comprising Fly Ash and Fluid Catalytic Cracking Residue as Aluminosilicate Precursor

2021 ◽  
Vol 11 (7) ◽  
pp. 3032
Author(s):  
Tuan Anh Le ◽  
Sinh Hoang Le ◽  
Thuy Ninh Nguyen ◽  
Khoa Tan Nguyen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Catalytic Cracking ◽  
Fluid Catalytic Cracking ◽  
High Alumina ◽  
Geopolymer Concrete ◽  
Sem Images

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.

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