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Articles 1 - 5 of 5
Full-Text Articles in Civil Engineering
Modelling The Hydrating Behaviour Of Fly-Ash In Blended Cements Using Thermodynamics, Nikki Shaji, Niall Holmes Dr., Mark Tyrer
Modelling The Hydrating Behaviour Of Fly-Ash In Blended Cements Using Thermodynamics, Nikki Shaji, Niall Holmes Dr., Mark Tyrer
Conference papers
This paper presents a new method to thermodynamically model the hydration behaviour of fly-ash (FA) blended cements by deriving individual phase descriptions depending on the proportion of FA in the blended cement. The predicted hydrated phase assemblage, pore solution chemistries and pH over 1,000 days of hydration and with increasing FA proportions are presented. The thermodynamic data for the FA phases are derived using oxide proportions and mineral compositions are copied directly into the PHREEQC input file. The FA phases take account of all minerals to give a more accurate description of its behaviour during hydration. The calcium aluminosilicate hydrate …
Review Of Fly-Ash As A Supplementary Cementitious Material, Nikki Shaji, Niall Holmes Dr., Mark Tyrer
Review Of Fly-Ash As A Supplementary Cementitious Material, Nikki Shaji, Niall Holmes Dr., Mark Tyrer
Conference papers
This paper presents a review of fly-ash as a Supplementary Cementitious Material (SCM) in concrete in terms of its effects on hydration and durability. The climate change agenda has focused the cement and concrete industry on using low embodied CO2 materials and much effort has been made on incorporating industrial by-products into cement as SCMs. With worldwide cement production (circa 4 billion tonnes) currently accounting for approximately 8% of global CO2 emissions and 7% of industry energy use, the use of suitable SCMs to partially replace cement in concrete is extremely important. However, while coal-fired power stations are in the …
Deriving Discrete Solid Phases From Csh-3t And Cshq End-Members To Model Cement Hydration In Phreeqc, Niall Holmes Dr., Colin Walker, Mark Tyrer, Denis Kelliher
Deriving Discrete Solid Phases From Csh-3t And Cshq End-Members To Model Cement Hydration In Phreeqc, Niall Holmes Dr., Colin Walker, Mark Tyrer, Denis Kelliher
Conference papers
This paper presents a cement hydration model over time using the CEMDATA thermodynamic database and a series of discrete solid phases (DSP) to represent calcium silicate hydrate (C-S-H) as a ternary (CSH-3T) and quaternary (CSHQ) solid solution. C-S-H in cement is amorphous and poorly crystalline with a range of molar Ca/Si ratios = 0.6-1.7 and displays strongly incongruent dissolution behaviour where the release of calcium into solution is several orders of magnitude greater than silicon. It is therefore important that any cement hydration model provides a credible account of this behaviour. C-S-H has been described in the CEMDATA thermodynamic database …
Modelling The Thermoelectric Properties Of Cement-Based Materials Using Finite Element Method And Effective Medium Theory, Lorenzo Stella, Conrad Johnston, Javier Troncoso, Piotr Chudzinski, Esther Orisakwee, Jorge Kohanoff, Ruchita Jani, Niall Holmes Dr., Brian Norton, Xiaoli Liu, Ming Qu, Hongxi Yin, Kazuaki Yazawa
Modelling The Thermoelectric Properties Of Cement-Based Materials Using Finite Element Method And Effective Medium Theory, Lorenzo Stella, Conrad Johnston, Javier Troncoso, Piotr Chudzinski, Esther Orisakwee, Jorge Kohanoff, Ruchita Jani, Niall Holmes Dr., Brian Norton, Xiaoli Liu, Ming Qu, Hongxi Yin, Kazuaki Yazawa
Conference papers
Because of the thermoelectric (TE) effect (or Seebeck effect), a difference of potential is generated as a consequence of a temperature gradient across a sample. The TE effect has been mostly studied and engineered in semiconducting materials and it already finds several commercial applications. Only recently the TE effect in cement-based materials has been demonstrated and there is a growing interest in its potential. For instance, a temperature gradient across the external walls of a building can be used to generate electricity. By the inverse of the TE effect (or Peltier effect), one can also seek to control the indoor …
Performance Modeling And Analysis Of A Thermoelectric Building Envelope For Space Heating, Xiaoli Liu, Ming Qu, Kazuaki Yazawa, Jorge Kohanoff, Piotr Chudzinski, Lorenzo Stella, Brian Norton, Niall Holmes Dr., Ruchita Jani, Hongxi Yin
Performance Modeling And Analysis Of A Thermoelectric Building Envelope For Space Heating, Xiaoli Liu, Ming Qu, Kazuaki Yazawa, Jorge Kohanoff, Piotr Chudzinski, Lorenzo Stella, Brian Norton, Niall Holmes Dr., Ruchita Jani, Hongxi Yin
Conference papers
To provide energy-efficient space heating and cooling, a thermoelectric building envelope (TBE) embeds thermoelectric devices in building walls. The thermoelectric device in the building envelope can provide active heating and cooling without requiring refrigerant use and energy transport among subsystems. Thus, the TBE system is energy and environmentally friendly. A few studies experimentally investigated the TBE under limited operating conditions, and only simplified models for the commercial thermoelectric module (TEM) were developed to quantify its performance. A holistic approach to optimum system performance is needed for the optimal system design and operation. The study developed a holistic TBE-building system model …