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.

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 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.

An Experiment Investigation on Physical and Mechanical Properties of High Strength Concrete with Suitable Admixture

2019 ◽  
Vol 972 ◽  
pp. 10-15
Author(s):  
B.C. Gayana ◽  
Mallikarjuna Shashanka ◽  
Avinash N. Rao ◽  
Karra Ram Chandar
Keyword(s):  
Mechanical Properties ◽  
High Strength Concrete ◽  
Construction Material ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Steel Fibers ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Conventional Concrete ◽  
Strength Concrete

Concrete is an essential construction material. Even-though conventional concrete performs and satisfy the structures under normal conditions, a few special situations require very high compressive strength of concrete. An experimental investigation is done to develop high strength concrete with suitable admixtures and steel fibers. The properties of fresh and hardened concrete with alccofine as partial replacement for binder and poly-carboxylate ether (Glenium 8233) and steel fibers is investigated for the workability and mechanical properties i.e., compressive, splitting tensile and flexural strength of concrete. Based on the results, the strength increased with the addition of alccofine compared to the control mix. Hence, by optimum percentage of alccofine, high strength of concrete of 112 MPa can be obtained.

Estimation of Compressive Strength of Recycled Aggregate High Strength Concrete Using Ultrasonic Pulse Velocity

2014 ◽  
Vol 605 ◽  
pp. 147-150
Author(s):  
Seong Uk Hong ◽  
Seung Hun Kim ◽  
Yong Taeg Lee
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Coarse Aggregate ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Recycled Aggregate ◽  
Strength Concrete ◽  
Recycled Coarse Aggregate

This study used the ultrasonic pulse velocity method, one of the non-destructive test methods that does not damage the building for maintenance of to-be-constructed concrete structures using recycled aggregates in order to estimate the compressive strength of high strength concrete structure using recycled coarse aggregate and provide elementary resources for technological establishment of ultrasonic pulse velocity method. 200 test pieces of high strength concrete 40, 50MPa using recycled coarse aggregate were manufactured by replacement rates (0, 30, 50, 100%) and age (1, 7, 28, 180days), and air curing was executed to measure compressive strength and wave velocity. As the result of compressive strength measurement, the one with age of 180day and design strength of 40MPa was 43.69MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 42.82, 41.22, 37.35MPa, and 50MPa was 52.50MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 49.02, 46.66, 45.30MPa, and while it could be seen that the test piece substituted with recycled aggregate was found to have lower strength than the test piece with natural aggregate only, but it still reached the design strength to a degree. The correlation of compressive strength and ultrasonic pulse velocity was found and regression analysis was conducted. The estimation formula for compressive strength of high strength concrete using recycled coarse aggregate was found to be Fc=0.069Vp4.05, R2=0.66

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 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.

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