Restricted Hydration of Mass-Cured Concrete Containing Fly Ash

1986 ◽  
Vol 86 ◽  
Author(s):  
R. H. Mills ◽  
N. Buenfeld
Keyword(s):  
Fly Ash ◽  
Relative Humidity ◽  
Portland Cement ◽  
Cement Paste ◽  
Strength Loss ◽  
Surface Strength ◽  
Curing Conditions ◽  
Evaporable Water

ABSTRACTCement paste and concrete specimens containing three different mixtures of portland cement (PC) and high-lime fly ash (FA) were subjected to various curing conditions, and the strengths, non-evaporable water, and porosities were compared with control mixes containing portland cement only. Strength and porosity data indicated that the cementing action of the mixtures was, in all cases, inferior to portland cement. For each mixture the strength loss resulting from imperfect curing, i.e. sealed or exposed to 50% relative humidity, was greater than for portland cement. In the case of concrete drying from one surface, strength differences were found, but these were not as clearly defined as those obtained in the paste specimens.

Restricted Hydration of Mass-Cured Concrete Containing Fly Ash

1986 ◽  
Vol 85 ◽  
Author(s):  
R. H. Mills ◽  
N. Buenfeld
Keyword(s):  
Fly Ash ◽  
Relative Humidity ◽  
Portland Cement ◽  
Cement Paste ◽  
Strength Loss ◽  
Surface Strength ◽  
Curing Conditions ◽  
Evaporable Water

ABSTRACTCement paste and concrete specimens containing three different mixtures of portland cement (PC) and high-lime fly ash (FA) were subjected to various curing conditions, and the strengths, non-evaporable water, and porosities compared with control mixes containing portland cement only. Strength and porosity data indicated that the cementing action of the mixtures was in all cases inferior to portland cement. For each mixture the strength loss resulting from imperfect curing, i.e. sealed or exposed to 50% relative humidity, was greater than for portland cement. In the case of concrete drying from one surface, strength differences were found, but these were not as clearly defined as those obtained in the paste specimens.

scholarly journals Effects of microbial agents to the properties of fly ash-based paste

2018 ◽  
Vol 195 ◽  
pp. 01012
Author(s):  
Kiki Dwi Wulandari ◽  
Januarti Jaya Ekaputri ◽  
Triwulan ◽  
Chikako Fujiyama ◽  
Davin H. E. Setiamarga
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Cement Paste ◽  
Construction Material ◽  
Concrete Strength ◽  
Self Healing ◽  
Concrete Mixtures ◽  
Microbial Agents ◽  
Portland Cement Paste ◽  
Geopolymer Paste

Specific microbial agents such as bacteria are often used in concrete to improve its performance. Some microbes act as self-healing agents to close cracks in concrete, and to increase concrete strength. This paper presents a study to observe the effects of microbe addition to two types of concrete mixtures the fly ash-based, as geopolymer paste, and portland cement paste containing fly ash. Furthermore, the investigation was conducted to compare the properties of each paste, such as its compressive strengths, specific gravities, porosity, microstructures, and XRay diffracting properties. The results indicate that microbial activities positively affected the properties of both, portland cement paste and geopolymer paste. The result reported here strongly suggests that fly ash can be used to produce a high quality, but environmental friendly construction material when it’s mixed together with useful microbes.

scholarly journals Effects of Mixing and Curing Temperature on the Strength Development and Pore Structure of Fly Ash Blended Mass Concrete

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Ki-Bong Park ◽  
Takafumi Noguchi
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Pore Structure ◽  
Weather Conditions ◽  
Strength Loss ◽  
Curing Temperature ◽  
Strength Development ◽  
Mass Concrete ◽  
Term Strength

The aim of this work is to know clearly the effects of temperature in response to curing condition, hydration heat, and outside weather conditions on the strength development of high-performance concrete. The concrete walls were designed using three different sizes and three different types of concrete. The experiments were conducted under typical summer and winter weather conditions. Temperature histories at different locations in the walls were recorded and the strength developments of concrete at those locations were measured. The main factors investigated that influence the strength developments of the obtained samples were the bound water contents, the hydration products, and the pore structure. Testing results indicated that the elevated summer temperatures did not affect the early-age strength gain of concrete made using ordinary Portland cement. Strength development was significantly increased at early ages in concrete made using belite-rich Portland cement or with the addition of fly ash. The elevated temperatures resulted in a long-term strength loss in both belite-rich and fly ash containing concrete. The long-term strength loss was caused by a reduction in the degree of hydration and an increase in the total porosity and amount of smaller pores in the material.

scholarly journals INFLUENCE OF RELATIVE HUMIDITY ON COMPRESSIVE STRENGTH OF FLY ASH CEMENT PASTE

2008 ◽  
Vol 73 (631) ◽  
pp. 1433-1441 ◽  
Author(s):  
Warangkana SAENGSOY ◽  
Toyoharu NAWA ◽  
Pipat TERMKHAJORNKIT
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Relative Humidity ◽  
Cement Paste

scholarly journals Resistance to Chemical Attack of Hybrid Fly Ash-Based Alkali-Activated Concretes

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3389
Author(s):  
William G. Valencia-Saavedra ◽  
Ruby Mejía de Gutiérrez
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Strength Loss ◽  
Cementitious Materials ◽  
Sodium Sulphate ◽  
Unburned Carbon ◽  
Chloride Permeability ◽  
Chemical Attack ◽  
Concrete Production ◽  
Alkali Activated

The environmental impacts related to Portland cement production in terms of energy consumption, the massive use of natural resources and CO2 emissions have led to the search for alternative cementitious materials. Among these materials, alkali-activated cements based on fly ash (FA) have been considered for concrete production with greater sustainability. In the present article, the chemical durability properties (resistance to sulphates, chloride permeability, and resistance to carbonation) of a hybrid alkali-activated concrete based on fly ash–ordinary Portland cement (FA/OPC) with proportions of 80%/20% were evaluated. It is noted that the FA was a low-quality pozzolan with a high unburned carbon content (20.67%). The results indicated that FA/OPC concrete had good durability with respect to the OPC concrete, with 95% less expansion in the presence of sodium sulphate and a 2% strength loss at 1100 days, compared with the 56% strength loss of the OPC concrete. In addition, FA/OPC showed lower chloride permeability. On the contrary, the FA/OPC was more susceptible to carbonation. However, the residual compressive strength was 23 MPa at 360 days of CO2 exposure. Based on the results, FA/OPC, using this type of FA, can be used as a replacement for OPC in the presence of these aggressive agents in the service environment.

Influence of Nano-Silica Dosage on Properties of Cement Paste Incorporating with High Calcium Fly Ash

2020 ◽  
Vol 841 ◽  
pp. 9-13
Author(s):  
Teewara Suwan ◽  
Peerapong Jitsangiam ◽  
Prinya Chindaprasirt
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Cement Paste ◽  
Construction Material ◽  
Internal Heat ◽  
Nano Silica ◽  
Industrial Sectors ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Cement And Concrete

Nanotechnology is receiving widespread attention in many industrial sectors, including construction material industry. One of the nano-scale admixtures, which has the potential to enhance the performance of cement and concrete, is known as Nano-silica (n-SiO2). In general, fly ash (FA) is currently used in cement and concrete industry for replacing the consumption of Portland cement (OPC) to reduce its production cost as well as to improve some specific required properties, e.g., workability or low internal heat liberation. However, the strength of hardened Portland cement is normally decreased when a higher amount of fly ash is presented. This research article is therefore pointed on the influence of nano-silica dosage on the properties of cement paste incorporating with high calcium fly ash. Seven different proportions of OPC:FA were prepared viz. 100:0, 80:20, 60:40, 50:50, 40:60, 20:80 and 0:100 by weight. The commercial grade nano-silica (in liquid form) was used as an admixture in those mixes by 0.0, 0.5, 1.0 and 1.5 wt% of the mixing water with a water-to-binder (w/b) ratio of 0.30. The results indicated that the addition of n-SiO2 improved the compressive strength of all mixtures (with and without high calcium FA) as the presence of n-SiO2 can be a source of silica and easily contribute to an additional formation of CSH in the cementing system, confirmed by the results of XRD analysis. The main findings show a potential approach of using n-SiO2 as an admixture for cement and concrete construction.

Effect of corrosive solutions on C-S-H microstructure in portland cement paste with fly ash

2016 ◽  
Vol 31 (5) ◽  
pp. 1002-1007 ◽  
Author(s):  
Qingjun Ding ◽  
Huan Wang ◽  
Chenguang Hu ◽  
Gaozhan Zhang
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Cement Paste ◽  
Portland Cement Paste

scholarly journals Properties of Ternary Blended Cement Containing Metakaolin and Fly Ash

2008 ◽  
Vol 5 (1) ◽  
pp. 13
Author(s):  
Mohd Fadzil Arshad ◽  
Megat Azmi Megat Johari ◽  
Muhd Norhasri Muhd Sidek ◽  
Mazlee Mohd Noor
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Construction Industry ◽  
Cement Paste ◽  
Laboratory Study ◽  
Ordinary Portland Cement ◽  
Blended Cement ◽  
Concrete Construction ◽  
Concrete Properties ◽  
And Performance

This paper presents the results of a laboratory study on the properties of Ternary Blended Cement (TBC) containing blends of ordinary Portland cement (OPC), Metakaolin (MK) and Fly Ash (FA). Analyses on the cementitious properties and engineering concrete properties containing TBC produced have been performed. The resulted was than compared with those of OPC and binary blended cementitious (BBC) systems containing OPC:MK and OPC:FA. In general, the results show that the inclusion of MK and FA in TBC alter the properties and performance of the cement paste and concrete to a certain degree as well as the resulting the TBC could potentially be used in the concrete construction industry.

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