scholarly journals Thermal Properties of Conventional and High-strength Concrete

2018 ◽  
Vol 245 ◽  
pp. 06005 ◽  
Author(s):  
Tatiana Musorina ◽  
Alexsander Katcay ◽  
Mikhail Petrichenko ◽  
Anna Selezneva
Keyword(s):  
Thermal Properties ◽  
Thermophysical Properties ◽  
High Strength Concrete ◽  
High Strength ◽  
Temperature Fluctuations ◽  
Conventional Concrete ◽  
Freeze Thaw ◽  
Strength Concrete ◽  
Concrete Properties ◽  
Cold Chamber

Important characteristics for the Nordic countries: a freeze-thaw resistance and an ability of a material to keep heat inside the building. This paper aims to define the thermophysical properties of a high-strength concrete, compare the discovered performance with the conventional concrete properties. With this object in mind two experiments in cold chamber “CHALLENGE 250” have been conducted and followed by analysis. In these experiments, the insulation of facades is beyond the framework of the investigation. Only the thermophysical properties of concrete are taken into account. The samples were affected by temperature fluctuations. Results from the experiments show that strength characteristics of a material are in indirect ratio to accumulation properties of a structure. This conclusion is directly related to porosity of material and additives. During 70 minutes, with outside temperature being below zero, the temperature inside the concrete dropped to an average. As the outside temperature increases significantly to more than zero, the temperature inside the concrete has become below average (continued to decline) in 70 minutes. The more strength of material, the better thermophysical properties. High-strength concrete is less susceptible to temperature fluctuations, therefore more heat-resistant. As mentioned in the paper below, the material has one disadvantage: this is a large cost per cubic meter.

scholarly journals Recycled Aggregate Self-curing High-strength Concrete

2017 ◽  
Vol 3 (6) ◽  
pp. 427-441 ◽  
Author(s):  
Alaa Ali Bashandy ◽  
Noha M. Soliman ◽  
Mahmoud Hamdy Abd Elrahman
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Water Evaporation ◽  
Hardened Concrete ◽  
Curing Agent ◽  
Conventional Concrete ◽  
Strength Concrete ◽  
Concrete Properties

The use of recycled aggregates from demolished constructions as coarse aggregates for concrete becomes a need to reduce the negative effects on the environment. Internal curing is a technique that can be used to provide additional moisture in concrete for more effective hydration of cement to reduce the water evaporation from concrete, increase the water retention capacity of concrete compared to the conventionally cured concrete. High strength concrete as a special concrete type has a high strength with extra properties compared to conventional concrete. In this research, the combination of previous three concrete types to obtain self-curing high-strength concrete cast using coarse recycled aggregates is studied. The effect of varying water reducer admixture and curing agent dosages on both the fresh and hardened concrete properties is studied. The fresh properties are discussed in terms of slump values. The hardened concrete properties are discussed in terms of compressive, splitting tensile, flexure and bond strengths. The obtained results show that, the using of water reducer admixture enhances the main fresh and hardened properties of self-curing high-strength concrete cast using recycled aggregate. Also, using the suggested chemical curing agent increased the strength compared to conventional concrete without curing.

Performance Deterioration of High Strength Concrete under Mixed Erosion and Freeze-Thaw Cycling

2010 ◽  
Vol 163-167 ◽  
pp. 1655-1660
Author(s):  
Jian Zhang ◽  
Bo Diao ◽  
Xiao Ning Zheng ◽  
Yan Dong Li
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Mass Loss ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
High Strength Concrete ◽  
High Strength ◽  
Freeze Thaw ◽  
Strength Concrete ◽  
Dynamic Modulus Of Elasticity

The mechanical properties of high strength concrete(HSC) were experimentally investigated under mixed erosion and freeze-thaw cycling according to ASTM C666(Procedure B), the erosion solution was mixed by weight of 3% sodium chloride and 5% sodium sulfate. The mass loss, relative dynamic modulus of elasticity, compressive strength, elastic modulus and other relative data were measured. The results showed that with the increasing number of freeze-thaw cycles, the surface scaled more seriously; the mass loss, compressive strength and elastic modulus continued to decrease; the relative dynamic modulus of elasticity increased slightly in the first 225 freeze-thaw cycles, then decreased in the following 75 cycles; the corresponding strain to peak stress decreased with the increase of freeze-thaw cycles. After 200 cycles, the rate of deterioration of concrete accelerated obviously.

scholarly journals A Study on the Thermal Properties of High-Strength Concrete Containing CBA Fine Aggregates

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1493 ◽  
Author(s):  
In-Hwan Yang ◽  
Jihun Park
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Ultrasonic Velocity ◽  
High Strength Concrete ◽  
High Strength ◽  
Unit Weight ◽  
Test Results ◽  
Strength Concrete ◽  
Fine Aggregates

The thermal conductivity of concrete is a key factor for efficient energy consumption in concrete buildings because thermal conductivity plays a significant role in heat transfer through concrete walls. This study investigated the effects of replacing fine aggregates with coal bottom ash (CBA) and the influence of curing age on the thermal properties of high-strength concrete with a compressive strength exceeding 60 MPa. The different CBA aggregate contents included 25%, 50%, 75%, and 100%, and different curing ages included 28 and 56 days. For concrete containing CBA fine aggregate, the thermal and mechanical properties, including the unit weight, thermal conductivity, compressive strength, and ultrasonic velocity, were measured. The experimental results reveal that the unit weight and thermal conductivity of the CBA concrete were highly dependent on the CBA content. The unit weight, thermal conductivity, and compressive strength of the concrete decreased as the CBA content increased. Relationships between the thermal conductivity and the unit weight, thermal conductivity and compressive strength of the CBA concrete were proposed in the form of exponential functions. The equations proposed in this study provided predictions that were in good agreement with the test results. In addition, the test results show that there was an approximately linear relationship between the thermal conductivity and ultrasonic velocity of the CBA concrete.

scholarly journals Tensile Properties of Very-High-Strength Concrete for Penetration-Resistant Structures

1999 ◽  
Vol 6 (5-6) ◽  
pp. 237-245 ◽  
Author(s):  
E.F. O’Neil ◽  
B.D. Neeley ◽  
J.D. Cargile
Keyword(s):  
Tensile Properties ◽  
High Strength Concrete ◽  
High Strength ◽  
Conventional Concrete ◽  
Strength Concrete ◽  
New Family ◽  
Concrete Mixtures ◽  
Study Results ◽  
Protective Structures ◽  
Very High

This paper describes the potential suitability of a new family of concrete mixtures for use in protective structures. Two very-high-strength concrete mixtures are discussed and experimental results of penetration studies on one of these are presented. The results are compared to penetration-study results of other, more conventional concrete mixtures, and the advantages of the very-high-strength mixtures are described.

scholarly journals Nano Alumina Based High Strength Concrete

2020 ◽  
Vol 9 (4) ◽  
pp. 256-363
Keyword(s):  
Mechanical Properties ◽  
High Strength Concrete ◽  
High Strength ◽  
Pulse Velocity ◽  
Hardened Concrete ◽  
Normal Concrete ◽  
Conventional Concrete ◽  
Tem Analysis ◽  
Strength Concrete ◽  
Nano Alumina

Very recently, the world of nano technology has initiated to fabricate new materials owing to the demand for their use in enhancing the properties of different materials in general and, materials used in the construction industry in particular. In this study, the results of an exhaustive experimental analysis, on the use of nano alumina with cement powder to enhance the grade and strength of concrete has been undertaken. The influence of the nano alumina in concrete with different proportions has been studied to assess mechanical properties of concrete with reference to normal concrete. The test results indicate that the use of nano alumina in concrete has enhanced the mechanical properties of hardened concrete. This nano alumina based high strength concrete (HSC) has an enhanced compressive strength of 64.17 N/mm2 (MPa) after 28 days, which is a significant improvement over normal concrete. All the mixes having nano alumina in different proportions gave better results as compared to normal conventional concrete mix. The Rebound Hammer, Ultrasonic Pulse Velocity, SEM and TEM analysis further validate the above findings.

scholarly journals IMPACT OF USING STONE POWDER AND MINERAL ADMIXTURES IN HIGH STRENGTH CONCRETE

2020 ◽  
Vol 4 (5) ◽  
pp. 82-87
Author(s):  
Afzal Basha Syed ◽  
Jayarami Reddy B ◽  
Sashidhar C
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Mineral Admixtures ◽  
Test Results ◽  
Concrete Technology ◽  
Split Tensile Strength ◽  
Conventional Concrete ◽  
Strength Concrete

In present era, high-strength concrete is progressively utilized in modern concrete technology and particularly in the construction of elevated structures. This examination has been directed to explore the properties of high-strength concrete that was delivered by using stone powder (SP) as an option of extent on sand after being processed. The aim of the research is to study the effect of replacement of sand with stone powder and substitution of cement with mineral admixtures (GGBS & Zeolite) on the mechanical properties of high strength concrete. The test results showed clear improvement in compression and split tensile nature of concrete by using stone powder and mineral admixtures together in concrete. The increment in the magnitude of compressive strength and split tensile strength are comparable with conventional concrete.

Specimen Size and Shape Effects on the Concrete Properties, Thermal Conductivity and Heat Generation from Hydration for Different Concrete Types

2019 ◽  
Vol 16 (10) ◽  
pp. 4072-4091 ◽  
Author(s):  
Ola Adel Qasim
Keyword(s):  
Thermal Conductivity ◽  
Reinforced Concrete ◽  
Heat Generation ◽  
High Strength Concrete ◽  
Concrete Beam ◽  
Concrete Strength ◽  
High Strength ◽  
Strength Concrete ◽  
Concrete Properties ◽  
The Difference

The environmental impact, manufacture and the application of concrete have many influences, some of which are influential and complex. Construction engineers are looking for modern ideas and methods that make the building more efficient in terms of functionality, cost, high strength, reduced overloads and increased efficiency of unlimited geometric shapes. The main factor in the improvement and development of concrete structures rely on the engineering characteristics of the substances. The developments in the construction materials, mix proportions, dimensions, mixing, and conditions (temperature) used to enhance the concrete technology, have important impacts on characteristics of concrete strength and heat development manner. The heat generation from concrete reveals the components of concrete materials and mix balances as well as the innovations in structure and environmental circumstances. This research presented an experimental investigation of the significance of the specimen’s shape and the size of the concrete properties durability, thermal conductivity and heat generation. Cylinders, prisms, and cubes of different sizes and shapes will be used. This research concluded that the effect of molds shape and size decreased when the (strength in compression, splitting tensile strength, flexural strength, and concrete density) increasing, that’s mean for ultra-high-strength concrete the difference is much smaller. The concrete hydration due to heat increases with increasing of the concrete strength and size, and the difference in heat transfer with the increasing of specimen’s size decreasing with increasing of concrete size. It is completely identified that the deformation and intensity of reinforced concrete beams depend on the size of the beam. Effect of concrete types (normal 26 MPa, high 46 MPa, and ultra-high-strength concrete 61 MPa) on the design of reinforced concrete beam was studied with three different depth (170, 155 and 150 mm). Results revealed that high strength and ultra-high-strength concrete was able to substitute for the reduction in beams size with the same strength. For concrete that is high or ultra-high-strength a reduction in the beam depth of about (8.82%) and (11.76%) compared to the normal concrete beam where achieved.

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