Influence of Curing Conditions on the Impact of Natural Aggregate Coatings on Concrete Performance

2011 ◽  
Vol 2232 (1) ◽  
pp. 25-33
Author(s):  
Jose F. Muñoz ◽  
Jacob B. Effinger ◽  
M. Isabel Tejedor ◽  
Marc A. Anderson ◽  
Steven M. Cramer
Keyword(s):  
Curing Conditions ◽  
Natural Aggregate ◽  
The Impact

scholarly journals Influence of Steam Curing Method on the Performance of Concrete Containing a Large Portion of Mineral Admixtures

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Mengyuan Li ◽  
Qiang Wang ◽  
Jun Yang
Keyword(s):  
Chloride Ion ◽  
Mineral Admixtures ◽  
Strength Development ◽  
Steam Curing ◽  
Chloride Permeability ◽  
Curing Conditions ◽  
Volume Stability ◽  
Ettringite Formation ◽  
The Impact ◽  
Reaction Degree

A comparison was made between the impact of raising the thermostatic temperature and the impact of prolonging the thermostatic time on the performance of steam-cured concrete containing a large portion of fly ash (FA) or ground granulated blast furnace slag (GGBS) by analysing the form removal strength, chemically combined water content, reaction degree, strength development, chloride permeability, and volume stability. For the materials and test conditions reported in this study, raising the thermostatic temperature is more favourable for concrete containing FA, as indicated by the significantly higher form removal strength and the higher growth of reaction degree of FA compared with prolonging the thermostatic time. With an increase in the thermostatic temperature, the hydration degree of a binder containing FA or GGBS initially increases and subsequently decreases. Although concrete containing FA can obtain satisfactory form removal strength with steam curing at 80°C, the late strength development of concrete containing FA is slow for the same curing conditions. The effect of the late performance of resistance to chloride ion permeability improved by FA is better than the effect improved by GGBS. The risk of destroying the structure of concrete containing a large portion of FA or GGBS due to delayed ettringite formation (DEF) is minimal when specimens were steam-cured at 80°C.

Mechanical Behavior of Heat Activated Film Adhesives

2021 ◽  
Author(s):  
Prabhat Janamanchi ◽  
Abhijit Dasgupta ◽  
Narendra Singh
Keyword(s):  
Mechanical Behavior ◽  
Thermal Exposure ◽  
Melting Transition ◽  
Preliminary Evaluation ◽  
Curing Conditions ◽  
Structural Applications ◽  
History Of ◽  
Favorable Conditions ◽  
The Impact ◽  
Curing Age

Abstract Heat activated film (HAF) adhesives enable the bonding of materials that are difficult to bond with conventional adhesives where one of the substrates is flexible. Although they are traditionally found in the context of industrial and structural applications, they are increasingly finding use in in electronic products. This paper provides a preliminary evaluation of the mechanical behavior of HAFs. Two commercial polyurethane HAF formulations (designated as HAF-II and HAF-III, for the purpose of this paper) were evaluated to assess the dependence of the mechanical properties on phase transitions and on the thermal exposure history of the material. Both factors were found to play a significant role in determining the overall usability of the materials. The melting transition occurs under 50°C for both materials, after which their stiffness drops significantly. Among the two, HAF-III is preferable as it undergoes a delayed melting transition, effectively extending the usable operating temperature range. As with any adhesive, there are several other factors that can influence the performance of adhesives such as post-curing age, storage, and curing conditions to name a few. The impact of these factors on the material’s strength is also discussed in brief and a recommendation for favorable conditions is provided.

Comparison of Mechanical Properties of Fly Ash Artificial Geopolymer Aggregates with Natural Aggregate

2015 ◽  
Vol 754-755 ◽  
pp. 290-295 ◽  
Author(s):  
Alida Abdullah ◽  
Ku Amirrul Rahman Ku Yin ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin ◽  
Mien Van Tran
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Specific Gravity ◽  
Water Absorption ◽  
Raw Materials ◽  
Construction Materials ◽  
High Water ◽  
Natural Aggregate ◽  
Materials Used ◽  
The Impact

This study was conducted to compare the mechanical properties of fly ash artificial geopolymer aggregates with natural aggregate (rock) in term of its impact strength, specific gravity and water absorption.The raw materials used were fly ash, sodium hydroxide, sodium silicate and natural aggregate. After the artificial geopolymer aggregate has been produced, its water absorption, specific gravity and aggregate impact test has been done. All results obtained were compared to natural aggregate. The result shows that the fly ash geopolymer aggregate are lighter than natural aggregate in term of its specific gravity. The impact value for fly ash artificial geopolymer aggregate slightly high compared to natural aggregate while it has high water absorption value compared to natural aggregate. As conclusion, the fly ash artificial geopolymer aggregate can be used as one of the construction materials in concrete as an alternative for coarse aggregate besides natural aggregate with more lightweight properties.

Influence of Different Curing Conditions on Shrinkage of Concrete

2013 ◽  
Vol 838-841 ◽  
pp. 36-41 ◽  
Author(s):  
Jing Chen ◽  
Xiao Huan Li ◽  
Feng Ling Wang ◽  
Fen Lian Xu
Keyword(s):  
Natural Condition ◽  
Polypropylene Fiber ◽  
Standard Condition ◽  
Concrete Cracking ◽  
Curing Conditions ◽  
Concrete Mix ◽  
The Impact ◽  
Variation Rule

Experiments for studying the shrinkage of concrete cured under three conditions were designed, and the impact of different curing conditions on the 28-day shrinkage and 180-day long-term shrinkage of concrete was researched. The results are as follows: There are significant influences of different curing conditions on shrinkage of concrete; The variation rule of 28-day shrinkage of concrete is consistent with that of 180-day shrinkage of concrete, the shrinkage of the concrete cured under standard condition is less than that cured under indoor natural condition, and larger than that cured under totally enclosed condition; In addition to mixing polypropylene fiber and expansive agents to optimize the proportions of concrete mix in the manufacturing process of concrete, adequate curing, after placing, is quite necessary for effectively controlling the shrinkage development of concrete, reducing the risk of concrete cracking and improving the quality of concrete structure.

Environmental Assessment of Recycled Aggregate

2015 ◽  
Vol 1106 ◽  
pp. 61-64 ◽  
Author(s):  
Tereza Pavlů ◽  
Vladimír Kočí ◽  
Magdaléna Šefflová
Keyword(s):  
Environmental Assessment ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycling Process ◽  
Natural Aggregate ◽  
Concrete Mixtures ◽  
Waste Production ◽  
Deformation Properties ◽  
The Impact ◽  
Diesel Production

The paper presents an environmental assessment of construction and demolition (C&D) waste production. The use of C&D waste carries a number of positive and negative aspects. These aspects should be compared to find the optimal way for recycled aggregate use. This study presents results of a fuel consumption survey of Czech recycling companies. Furthermore, there are evaluated impact categories of the connection with the diesel production and diesel burning during recycling process. Finally, it is shown comparison with database data for mining of natural aggregate. In addition, the results of previous investigation of the impact of natural aggregate substitution by recycled aggregate in concrete mixtures on mechanical and deformation properties of recycled concrete are presented.

scholarly journals Impact Resistance For Ready Mix Concrete Plant Waste Concrete Aggregate

2020 ◽  
Vol 9 (1) ◽  
pp. 2311-2315
Keyword(s):  
Impact Test ◽  
Impact Resistance ◽  
Concrete Aggregate ◽  
Aggregate Concrete ◽  
Natural Aggregate ◽  
Waste Concrete ◽  
Drop Weight ◽  
Plant Waste ◽  
The Impact ◽  
Ready Mix Concrete

The investigation to learn about the effect resistance for Ready Mix Concrete plant waste utilized in new concrete substitute of Natural aggregate. In concrete trade natural aggregate with RMC plant waste of 7 days old waste concrete aggregate in 20% interval up to 100%. In the impact testing machine a drop weight was developed to govern impact resistance on Natural Aggregate concrete & RMC plant waste aggregate concrete. In aspect ratio (l/d) as 60 conducted Impact test on NAC & RMC waste. The samples of M40 strength of concrete. The Impact test conducted on samples as per ACI-544 committee method and verified by drop weight methods. RMC waste concrete aggregate exhibited with variation of different percentage test results of impact strength energy. The impact resistance significantly increases by additions of RMC plant waste concrete aggregate.

scholarly journals Flexural Behaviour of Cementitious Mortars with the Addition of Basalt Fibres

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1334
Author(s):  
Małgorzata Wydra ◽  
Piotr Dolny ◽  
Grzegorz Sadowski ◽  
Jadwiga Fangrat
Keyword(s):  
Flexural Strength ◽  
Basalt Fibre ◽  
Polypropylene Fibres ◽  
Curing Conditions ◽  
Water To Cement Ratio ◽  
Different Temperatures ◽  
Flexural Tests ◽  
Short Time ◽  
Micro Silica ◽  
The Impact

The results of flexural tests of basalt fibre-reinforced cementitious mortars in terms of flexural strength and the occurrence of the bridging effect are summarised. Mixture proportions and curing conditions were altered for various series. The main parameters concerning mixture proportions were water to cement ratio (w/c), micro-silica and plasticiser addition and fibre dosage (1%, 3% and 6.2% by binder’s mass). Various curing conditions were defined by different temperatures, humidity and time. The influence of the amount of water inside the pores of the hardened cementitious matrix on the flexural strength values, as far as the impact of the alkaline environment on basalt fibres’ performance is concerned, was underlined. The designation of flexural strength and the analysis of post-critical deformations were also performed on the reference series without fibres and with the addition of more common polypropylene fibres. The bridging effect was observed only for the basalt fibre-reinforced mortar specimens with a relatively low amount of cement and high w/c ratio, especially after a short time of hardening. For the lowest value of w/c ratio (equalling 0.5), the bridging effect did not occur, but flexural strength was higher than in the case of non-reinforced specimens. Comparing mortars with the addition of basalt and polypropylene fibres, the former demonstrated higher values of flexural strength (assuming the same percentage dosage by the mass of the binder). Nevertheless, the bridging effect in that case was obtained only for polypropylene fibres.

scholarly journals Shrinkage Mitigation of an Ultra-High Performance Concrete Submitted to Various Mixing and Curing Conditions

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3982
Author(s):  
Cédric Androuët ◽  
Jean-Philippe Charron
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Water Immersion ◽  
Autogenous Shrinkage ◽  
Early Age ◽  
Curing Conditions ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
The Impact

Ultra-High Performance Concretes (UHPC) are cement-based materials with a very low water-to-binder ratio that present a very-high compressive strength, high tensile strength and ductility as well as excellent durability, making them very interesting for various civil engineering applications. However, one drawback of UHPC is their pretty high autogenous shrinkage stemming from their very low water-to-binder ratio. There are several options to reduce UHPC shrinkage, such as the use of fibers (steel fibers, polypropylene fibers, wollastonite microfibers), shrinkage-reducing admixtures (SRA), expansive admixtures (EA), saturated lightweight aggregates (SLWA) and superabsorbent polymers (SAP). Other factors related to curing conditions, such as humidity and temperature, also affect the shrinkage of UHPC. The aim of this paper is to investigate the impact of various SRA, different mixing and curing conditions (low to moderate mixing temperatures, moderate to high relative humidity and water immersion) as well as different curing starting times and durations on the shrinkage of UHPC. The major importance of the initial mixing and curing conditions has been clearly demonstrated. It was shown that the shrinkage of the UHPC was reduced by more than 20% at early-age and long-term when the fresh UHPC temperature was closer to 20 °C. In addition, curing by water immersion led to drastic reductions in shrinkage of up to 65% and 30% at early-age and long-term, respectively, in comparison to a 20% reduction for fog curing at early-age. Finally, utilization of a liquid polyol-based SRA allowed for reductions of 69% and 63% of early-age and long-term shrinkages, respectively, while a powder polyol-based SRA provided a decrease of 47% and 35%, respectively.

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