Numerical Simulation of Autogenous Shrinkage of Eco-Friendly Blended Portland Cements Using a Multi-Component Hydration Model

2008 ◽  
Vol 569 ◽  
pp. 261-264 ◽  
Author(s):  
Xiao Yong Wang ◽  
Han Seung Lee ◽  
Seung Min Lim
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Autogenous Shrinkage ◽  
Heat Of Hydration ◽  
Curing Temperature ◽  
Portland Cements ◽  
Influence Of Water ◽  
Hydration Model ◽  
Numerical Program

Fly ash and granulated blast-furnace slag, which are used as blends of Portland cement, are waste materials produced in electric and energy industry. Due to excellent durability, low heat of hydration, energy-saving, resource-conserving, and generally less expensive than ordinary Portland cement, blends Portland cements is used increasingly in construction industry. Both ecology benefit and economic benefit can be achieved by using blended Portland cement. Addition of blended components to cement, especially such as fly ash or silica fume, will lead to a densification of the microstructure. The autogenous shrinkage deformation will increase and the following autogenous shrinkage crack will do harm to durability of concrete structure. In this paper, based on the multi-component hydration model, a numerical program is built to predict autogenous shrinkage of ordinary Portland cement and blended Portland cement. The numerical program considers the influence of water to cement ratio, curing temperature, particle size distribution, cement mineral components on hydration process and autogenous shrinkage. The prediction result agrees well with experiment result.

Numerical Simulation of Heat Evolution of Eco-Friendly Blended Portland Cements Using a Multi-Component Hydration Model

2008 ◽  
Vol 569 ◽  
pp. 257-260 ◽  
Author(s):  
Xiao Yong Wang ◽  
Han Seung Lee ◽  
Ki Bong Park
Keyword(s):  
Portland Cement ◽  
Pozzolanic Reaction ◽  
Heat Evolution ◽  
Curing Temperature ◽  
Evolution Process ◽  
Waste Materials ◽  
Portland Cements ◽  
Influence Of Water ◽  
Mineral Components ◽  
Hydration Model

With the development of concrete industry, the necessity for utilizing waste materials and decreasing overall energy consumption is becoming increasingly obvious. Fly ash and granulated blast-furnace slag, which are used as blends of Portland cement, are waste materials produced in electric and energy industry, and concretes made with them can have properties similar to ones made with pure Portland cement at lower cost per unit volume. By using blended Portland cement, both ecology benefit and economic benefit can be achieved. Due to the pozzolanic reaction between calcium hydroxide and blended components, compared with ordinary Portland cement, hydration process of blended Portland cement is more complex. In this paper, based on a multi-component hydration model, a numerical model which can simulate heat evolution process of blended Portland cements is built. The influence of water to cement ratio, curing temperature, particle size distribution of cement paste and blended Portland material, and cement mineral components on heat evolution process is considered. The prediction result agrees well with experiment result.

scholarly journals Thermal Properties of Calcium Sulphoaluminate Cement as an Alternative to Ordinary Portland Cement

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7011
Author(s):  
Małgorzata Gołaszewska ◽  
Barbara Klemczak ◽  
Jacek Gołaszewski
Keyword(s):  
Activation Energy ◽  
Portland Cement ◽  
Apparent Activation Energy ◽  
Thermal Behaviour ◽  
Ordinary Portland Cement ◽  
Isothermal Calorimetry ◽  
Heat Of Hydration ◽  
Curing Temperature ◽  
Cement Pastes ◽  
Calcium Sulphoaluminate

This paper presents the results of research into the heat of hydration and activation energy of calcium sulphoaluminate (CSA) cement in terms of the dependence on curing temperature and water/cement ratio. Cement pastes with water/cement ratios in the range of 0.3–0.6 were tested by isothermal calorimetry at 20 °C, 35 °C and 50 °C, with the evolved hydration heat and its rate monitored for 168 h from mixing water with cement. Reference pastes with ordinary Portland cement (OPC) were also tested in the same range. The apparent activation energy of CSA and OPC was determined based on the results of the measurements. CSA pastes exhibited complex thermal behaviour that differed significantly from the thermal behaviour of ordinary Portland cement. The results show that both the w/c ratio and elevated temperature have a meaningful effect on the heat emission and the hydration process of CSA cement pastes. The determined apparent activation energy of CSA revealed its substantial variability and dependence, both on the w/c ratio and the curing temperature.

scholarly journals Strength Development and Elemental Distribution of Dolomite/Fly Ash Geopolymer Composite under Elevated Temperature

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 1015 ◽  
Author(s):  
Emy Aizat Azimi ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Petrica Vizureanu ◽  
Mohd Arif Anuar Mohd Salleh ◽  
Andrei Victor Sandu ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Fly Ash ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Raw Materials ◽  
Liquid Sodium ◽  
Strength Development ◽  
Elemental Distribution ◽  
Distribution Analysis ◽  
Geopolymer Composites

A geopolymer has been reckoned as a rising technology with huge potential for application across the globe. Dolomite refers to a material that can be used raw in producing geopolymers. Nevertheless, dolomite has slow strength development due to its low reactivity as a geopolymer. In this study, dolomite/fly ash (DFA) geopolymer composites were produced with dolomite, fly ash, sodium hydroxide, and liquid sodium silicate. A compression test was carried out on DFA geopolymers to determine the strength of the composite, while a synchrotron Micro-Xray Fluorescence (Micro-XRF) test was performed to assess the elemental distribution in the geopolymer composite. The temperature applied in this study generated promising properties of DFA geopolymers, especially in strength, which displayed increments up to 74.48 MPa as the optimum value. Heat seemed to enhance the strength development of DFA geopolymer composites. The elemental distribution analysis revealed exceptional outcomes for the composites, particularly exposure up to 400 °C, which signified the homogeneity of the DFA composites. Temperatures exceeding 400 °C accelerated the strength development, thus increasing the strength of the DFA composites. This appears to be unique because the strength of ordinary Portland Cement (OPC) and other geopolymers composed of other raw materials is typically either maintained or decreases due to increased heat.

Heat of hydration of Portland Cement–Metakaolin–Fly ash (PC–MK–PFA) blends

2008 ◽  
Vol 38 (6) ◽  
pp. 832-840 ◽  
Author(s):  
David G. Snelson ◽  
Stan Wild ◽  
Martin O'Farrell
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Heat Of Hydration

A trial construction of high durability railway viaducts with local aggregates

2019 ◽  
Author(s):  
Kotaro Kawamura ◽  
Joe Takemura ◽  
Shigenobu Iguchi ◽  
Tsutomu Yoshida ◽  
Masashi Kobayashi
Keyword(s):  
Fly Ash ◽  
Side Effects ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
The Other ◽  
Strength Concrete ◽  
High Durability ◽  
Sound Barrier ◽  
Early Strength ◽  
Structural Measure

<p>We are carrying out a construction project of new railroad viaducts. These new railroad viaducts are constructing using about 110,000 m<span>3</span> volume concrete. In this construction place, it is difficult for us to get low ASR-reactive aggregates and it is expected to be supplied with snowmelt water on the viaducts in winter. Then we tested ASR-reactive these local aggregates and found an effective mixed ratio of fly-ash is 20% of cement. On the other hand, various side effects were also expected by using fly-ash. For example, initial cracking due to contraction, early strength concrete, bleeding, etc. Therefore, we repeated various tests and examined and carried out a method that could ensure the same construction method and quality as when using ordinary Portland cement, even with fly-ash. Also, we adopted a structure that is unlikely to be affected by rainwater as a structural measure. For example, the entire adoption of a ramen type viaduct that has eliminated bearings, adoption of FRP sound barrier, etc. Then we made it possible to build highly durable railway viaducts by these various measures of materials and structures.</p>

scholarly journals Hydration and Microwave Curing Temperature Interactions of Repair Mortars

2021 ◽  
Vol 03 (04) ◽  
pp. 1-1
Author(s):  
Pal S. Mangat ◽  
◽  
Shahriar Abubakri ◽  
Konstantinos Grigoriadis ◽  
Vincenzo Starinieri ◽  
...  
Keyword(s):  
Portland Cement ◽  
Heat Of Hydration ◽  
Curing Temperature ◽  
Early Age ◽  
Normal Density ◽  
Concrete Repair ◽  
Microwave Curing ◽  
Polymer Addition ◽  
Curing Period ◽  
Repair Materials

Microwave curing of repair patches provides an energy efficient technique for rapid concrete repair. It has serious economic potential due to time and energy saving especially for repairs in cold weather which can cause work stoppages. However, the high temperatures resulting from the combination of microwave exposure and accelerated hydration of cementitious repair materials need to be investigated to prevent potential durability problems in concrete patch repairs. This paper investigates the time and magnitude of the peak hydration temperature during microwave curing (MC) of six cement based concrete repair materials and a CEM II mortar. Repair material specimens were microwave cured to a surface temperature of 40-45 °C while their internal and surface temperatures were monitored. Their internal temperature was further monitored up to 24 hours in order to determine the effect of microwave curing on the heat of hydration. The results show that a short period of early age microwave curing increases the hydration temperature and brings forward the peak heat of hydration time relative to the control specimens which are continuously exposed to ambient conditions (20 °C, 60% RH). The peak heat of hydration of normal density, rapid hardening Portland cement based repair materials with either pfa or polymer addition almost merges with the end of microwave curing period. Similarly, lightweight polymer modified repair materials also develop heat of hydration rapidly which almost merges with the end of microwave curing period. The peak heat of hydration of normal density ordinary Portland cement based repair materials, with and without polymer addition, occurs during the post microwave curing period. The sum of the microwave curing and heat of hydration temperatures can easily exceed the limit of about 70 °C in some materials at very early age, which can cause durability problems.

High Performance Concrete with Ternary Binders

2018 ◽  
Vol 761 ◽  
pp. 120-123 ◽  
Author(s):  
Vlastimil Bílek ◽  
David Pytlík ◽  
Marketa Bambuchova
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume ◽  
High Performance ◽  
Ordinary Portland Cement ◽  
High Performance Concrete ◽  
Fresh Concrete ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
Condensed Silica Fume

Use a ternary binder for production of a high performance concrete with a compressive strengths between 120 and 170 MPa is presented. The water to binder ratio of the concrete is 0.225 and the binder is composed of Ordinary Portland Cement (OPC), condensed silica fume (CSF), ground limestone (L), fly ash (FA) and metakaoline (MK). The dosage of (M + CSF) is kept at a constant level for a better workability of fresh concrete. Different workability, flexural and compressive strengths were obtained for concretes with a constant cement and a metakaoline dosage, and for a constant dosage (FA + L) but a different ratio FA / L. An optimum composition was found and concretes for other tests were designed using this composition.

scholarly journals Influence of Amount of Calcareous Fly Ash on Heat of Hydration of Portland Cement

2019 ◽  
Vol 603 ◽  
pp. 042081
Author(s):  
Patrycja Miera ◽  
Jacek Golaszewski ◽  
Zbigniew Giergiczny
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Heat Of Hydration

scholarly journals Difference in Strength Development between Cement-Treated Sand and Mortar with Various Cement Types and Curing Temperatures

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4999
Author(s):  
Lanh Si Ho ◽  
Kenichiro Nakarai ◽  
Kenta Eguchi ◽  
Yuko Ogawa
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Bound Water ◽  
Curing Temperature ◽  
Strength Development ◽  
Early Age ◽  
Cement Type ◽  
A Value ◽  
Water To Cement Ratio ◽  
Novel Method

To improve the strength of cement-treated sand effectively, the use of various cement types was investigated at different curing temperatures and compared with the results obtained from similar mortars at higher cement contents. The compressive strengths of cement-treated sand specimens that contained high early-strength Portland cement (HPC) cured at elevated and normal temperatures were found to be higher than those of specimens that contained ordinary Portland cement (OPC) and moderate heat Portland cement at both early and later ages. At 3 days, the compressive strength of the HPC-treated sand specimen, normalized with respect to that of the OPC under normal conditions, is nearly twice the corresponding value for the HPC mortar specimens with water-to-cement ratio of 50%. At 28 days, the normalized value for HPC-treated sand is approximately 1.5 times higher than that of mortar, with a value of 50%. This indicates that the use of HPC contributed more to the strength development of the cement-treated sand than to that of the mortar, and the effects of HPC at an early age were higher than those at a later age. These trends were explained by the larger quantity of chemically bound water observed in the specimens that contained HPC, as a result of their greater alite contents and porosities, in cement-treated sand. The findings of this study can be used to ensure the desired strength development of cement-treated soils by considering both the curing temperature and cement type. Furthermore, they suggested a novel method for producing a high internal temperature for promoting the strength development of cement-treated soils.

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