scholarly journals Influence of steam curing on the pore structures and mechanical properties of fly-ash high performance concrete prepared with recycled aggregates

2016 ◽  
Vol 71 ◽  
pp. 77-84 ◽  
Author(s):  
Andreu Gonzalez-Corominas ◽  
Miren Etxeberria ◽  
Chi Sun Poon
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Recycled Aggregates ◽  
Steam Curing ◽  
Pore Structures

scholarly journals Sulfate Resistance of Recycled Aggregate Concrete with GGBS and Fly Ash-Based Geopolymer

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1247 ◽  
Author(s):  
Jianhe Xie ◽  
Jianbai Zhao ◽  
Junjie Wang ◽  
Chonghao Wang ◽  
Peiyan Huang ◽  
...  
Keyword(s):  
Fly Ash ◽  
Construction Projects ◽  
High Performance ◽  
High Performance Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Concrete ◽  
Sulfate Resistance ◽  
Coarse Aggregates

There is a constant drive for the development of ultra-high-performance concrete using modern green engineering technologies. These concretes have to exhibit enhanced durability and incorporate energy-saving and environment-friendly functions. The object of this work was to develop a green concrete with an improved sulfate resistance. In this new type of concrete, recycled aggregates from construction and demolition (C&D) waste were used as coarse aggregates, and granulated blast furnace slag (GGBS) and fly ash-based geopolymer were used to totally replace the cement in concrete. This study focused on the sulfate resistance of this geopolymer recycled aggregate concrete (GRAC). A series of measurements including compression, X-ray diffraction (XRD), and scanning electron microscopy (SEM) tests were conducted to investigate the physical properties and hydration mechanisms of the GRAC after different exposure cycles in a sulfate environment. The results indicate that the GRAC with a higher content of GGBS had a lower mass loss and a higher residual compressive strength after the sulfate exposure. The proposed GRACs, showing an excellent sulfate resistance, can be used in construction projects in sulfate environments and hence can reduce the need for cement as well as the disposal of C&D wastes.

The Effect of Homogenization Procedure on Mechanical Properties of High-Performance Concrete with Partial Replacement of Cement by Supplementary Cementitious Materials

2019 ◽  
Vol 292 ◽  
pp. 102-107 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Karel Šeps ◽  
Roman Chylík ◽  
Vladimír Hrbek
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Water Content ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Depth Of Penetration ◽  
Cement Additive

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.

scholarly journals Assessment of Mechanical Properties and Damage of High Performance Concrete Subjected to Magnesium Sulfate Environment

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Sheng Cang ◽  
Xiaoli Ge ◽  
Yanlin Bao
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Magnesium Sulfate ◽  
Damage Evolution ◽  
High Performance ◽  
Damage Mechanics ◽  
High Performance Concrete ◽  
Pulse Velocity ◽  
Sulfate Attack ◽  
Exponential Fitting

Sulfate attack is one of the most important problems affecting concrete structures, especially magnesium sulfate attack. This paper presents an investigation on the mechanical properties and damage evolution of high performance concrete (HPC) with different contents of fly ash exposure to magnesium sulfate environment. The microstructure, porosity, mass loss, dimensional variation, compressive strength, and splitting tensile strength of HPC were investigated at various erosion times up to 392 days. The ultrasonic pulse velocity (UPV) propagation in HPC at different erosion time was determined by using ultrasonic testing technique. A relationship between damage and UPV of HPC was derived according to damage mechanics, and a correlation between the damage of HPC and erosion time was obtained eventually. The results indicated that (1) the average increasing amplitude of porosity for HPCs was 34.01% before and after exposure to magnesium sulfate solution; (2) the damage evolution of HPCs under sulfate attack could be described by an exponential fitting; (3) HPC containing 20% fly ash had the strongest resistance to magnesium sulfate attack.

The Relationship of Compressive Strength and Tensile Strength of High Performance Concrete

2014 ◽  
Vol 627 ◽  
pp. 385-388 ◽  
Author(s):  
Jeong Eun Kim ◽  
Wan Shin Park ◽  
Song Hui Yun ◽  
Yong Il Jang ◽  
Hyun Do Yun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
High Performance ◽  
High Performance Concrete ◽  
Predicted Values ◽  
Relationship Of ◽  
Furnace Slag

Fly ash and blast furnace slag dumped not only pollutes environment, but also consumes landfills. With the aim of sustainable development, the isolated contribution of fly ash and blast furnace slag in concrete to the mechanical properties of frame concrete is investigated. An experimental study is conducted to investigate mechanical properties of high performance concrete. Test variables are the replacement levels for FA series (10%, 20% and 30%) and for BS series (10%, 30%, 50% and 70%) in place of part of cement. Compressive, splitting tensile strength, modulus of elasticity and flexural strength tests were carried out to evaluate the mechanical properties for up to 7days and 28 days. The mechanical properties of high performance concrete compared with predicted values by ACI 318-02 Code, EC 2-02, JSCE Code, KCI Code and proposed Eq.

Study on Mechanical Properties of High Volume Fly Ash Concrete

2013 ◽  
Vol 339 ◽  
pp. 638-641 ◽  
Author(s):  
Ling Mei Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Mineral Admixture ◽  
Concrete Compressive Strength ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash

With the acceleration of economic development, high-performance concrete applied more widespread due to its own merit. A certain amount of mineral admixture important role in the performance of high-performance concrete. This paper studies the high ash (30% -50%) of fly ash concrete compressive strength, splitting tensile strength, static elastic modulus and other mechanical properties.

scholarly journals Long Term Behavior of Ultra High-Performance Concrete

2021 ◽  
pp. 36-54
Author(s):  
Zeinab A. Etman ◽  
Noha M. Soliman ◽  
Mahmoud M. Abou Raia
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Fine Sand ◽  
Time Behavior ◽  
Quartz Powder ◽  
Ultra High Performance Concrete ◽  
Concrete Technology ◽  
Fineness Modulus

Ultra-High-Performance Concrete (UHPC) is one of the important types of concrete technology breakthroughs in the 21st century. It achieved high results of mechanical properties, durability (resistance fire) and bonding strength. The aim of paper is to evaluate the long-time behavior of UHPC. The main variables were finesse modulus of sand, crushed quartz powder, fly ash and metakaolin and methods of curing (water& hot).The sand with different fineness modulus(3.2, 2.36 and 1.9) were used, Crushed quartz powder with ratio (10%, 20% and 30%) as a replacement of sand was used. Fly ash and metakaolin, with of (10%, 20%, 30 and 40%) and (5%, 10% and 15%) as a replacement of cement; respectively. The effect of these variables on the mechanical properties (compressive, tensile, flexural strength) at different ages. Also, the drying shrinkage strain was evaluated. The results showed that using and with fineness modulus (1.9), 20% ratio of crushed quartz powder to fine sand (CQ/S), 20% of fly ash to cement (FA/C) and 5% of metakaolin to cement (MK/C) give the best proportions of UHPC. The compressive strength for this mix was 900 kg/ cm2 .

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