Processing math: 100%
  • Title/Summary/Keyword: Engineering Properties of concrete

Search Result 2,681, Processing Time 0.029 seconds

Mechanical Properties of Hwangtoh-Based Alkali-Activated Concrete

  • Yang, Keun-Hyeok;Hwang, Hey-Zoo;Lee, Seol
    • Architectural research
    • /
    • v.11 no.1
    • /
    • pp.25-33
    • /
    • 2009
  • This study presents the testing of 15 hwangtoh-based cementless concrete mixes to explore the significance and limitations of the development of eco-friendly concrete without carbon dioxide emissions while maintaining various beneficial effects. Hwangtoh, which is a kind of kaolin, was incorporated with inorganic materials, such as calcium hydroxide, to produce a cement-less binder. The main variables investigated were the water-to-binder ratio and fine aggregate-to-total aggregate ratio to ascertain the reliable mixing design of hwangtoh-based cementless concrete. The variation of slump with elapsed time was recorded in fresh concrete specimens. Mechanical properties of hardened concrete were also measured: including compressive strength gain, splitting tensile strength, moduli of rupture and elasticity, stress-strain relationship, and bond resistance. In addition, mechanical properties of hwangtoh-based cement-less concrete were compared with those of ordinary portland cement (OPC) concrete and predictions obtained from the design equations specified in ACI 318-05 and CEB-FIP for OPC concrete, wherever possible. Test results show that the mechanical properties of hwangtoh-based concrete were significantly influenced by the water-to-binder ratio and to less extend by fine aggregate-to-total aggregate ratio. The moduli of rupture and elasticity of hwangtoh-based concrete were generally lower than those of OPC concrete. In addition, the stress-strain and bond stress-slip relationships measured from hwangtoh-based concrete showed little agreement with the design model specified in CEB-FIP. However, the measured moduli of rupture and elasticity, and bond strength were higher than those given in ACI 318-05 and CEB-FIP. Overall, the test results suggest that the hwangtoh-based concrete shows highly effective performance and great potential as an environmental-friendly building material.

Properties and durability of concrete with olive waste ash as a partial cement replacement

  • Tayeh, Bassam A.;Hadzima-Nyarko, Marijana;Zeyad, Abdullah M.;Al-Harazin, Samer Z.
    • Advances in concrete construction
    • /
    • v.11 no.1
    • /
    • pp.59-71
    • /
    • 2021
  • This research aims to study the utilization of olive waste ash (OWA) in the production of concrete as a partial substitute for cement. Effects of using OWA on the physical and mechanical properties of concrete mixtures have been investigated. This is done by carrying out tests involving the addition of various percentages of OWA to cement (0%, 5%, 10% and 15%). For each percentage, tests were performed on both fresh and hardened concrete; these included slump test, unit weight test and compressive strength test after 7, 28 and 90 days. Durability tests were investigated in solutions containing 5% NaOH and MgSO4 by weight of water. In addition, resistance to high temperatures was tested by subjecting the cubes to high temperatures of up to 170℃. The results of this research indicate that a higher percentage of OWA gives a lower compressive strength and lower workability but higher performance in terms of durability against both different weather conditions and high temperatures.

Effect of horizontal joints on structural behavior of sustainable self-compacting reinforced concrete beams

  • Ibrahim, Omar Mohamed Omar;Heniegal, Ashraf Mohamed;Ibrahim, Khamis Gamal;Agwa, Ibrahim Saad
    • Advances in concrete construction
    • /
    • v.10 no.5
    • /
    • pp.455-462
    • /
    • 2020
  • This study investigated the effect of horizontal casting joints on the mechanical properties and structural behavior of sustainable self-compacting reinforced concrete beams (SCRCB). The experimental research consisted of two stages. The first stage used four types of concrete mixtures which were produced to indicate the effects of cement replaced with cement waste at 0%, 5%, 10%, and 15% by weight of cement content on fresh concrete properties of self-compacting concrete (SCC) such as, passing ability, filling ability, and segregation resistance. In addition, mechanical properties such as compressive, tensile, and flexural strength were also studied. The second stage selected the best mixture from the first stage and studied the effect of horizontal casting joints on the structural behavior of sustainable SCRCBs. The effect of horizontal casting joints on the mechanical properties and structural behavior were at the 25%, 50%, 75%, and 100% of sample height. Load deflection, failure mode, and theoretical analysis were studied. Results indicated that the incorporation of replacement with cement waste by 5% to 10% led to economic and environmental advantages, and the results were acceptable for fresh and mechanical properties. The results indicated that delaying the time for casting the second layer and increasing the cement waste in concrete mixtures had a great effect on the mechanical properties of SCC. The ultimate load capacity of horizontal casting joints reinforced concrete beams slightly decreased compared with the control beam. The maximum deflection of casting joint beams with 75% of samples height is similar with the control beam. The experimental results of reinforced concrete beams were substantially acceptable with the theoretical results. The failure modes obtained the best forced casting joint on the structural behavior at 50% height of casting in the beam.

Improvement of bond strength and durability of concrete incorporating high volumes of class F fly ash

  • Wu, Chung-Hao;Chen, Chien-Jung;Lin, Yu-Feng;Lin, Shu-Ken
    • Advances in concrete construction
    • /
    • v.12 no.5
    • /
    • pp.367-375
    • /
    • 2021
  • This study experimentally investigated the improvement of bond strength and durability of concrete containing high volume fly ash. Concrete mixtures made with 0%, 25% and 60% replacement of cement with class F fly ash were prepared. Water-binder ratios ranged from 0.28 to 0.72. The compressive, flexural and pullout bond strength, the resistance to chloride-ion penetration, and the water permeability of concrete were measured and presented. Test results indicate that except for the concretes at early ages, the mechanical properties, bond strength, and the durability-related chloride-ion permeability and water permeability of concrete containing high volume (60% cement replacement) fly ash were obviously superior to the concrete without fly ash at later ages of beyond 56 days. The enhanced bond strength for the high volume fly-ash concrete either with or without steel confinement is a significant finding which might be valuable for the structural application.

The Study on the Engineering Properties of High-Strength Glossy Concrete Tiles Using Waste Concrete Powders (재생 미분말을 적용한 고강도 광택 콘크리트 마감재의 공학적 특성에 관한 연구)

  • Choi Sun Mi;Jung Ji Yong;Jung Eun Hye;Kim Jin Man
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2005.05b
    • /
    • pp.465-468
    • /
    • 2005
  • This Study is concerned workability and the physical properties for practical use of waste concrete powder originated from the manufacturing progress of waste concrete aggregate and it apply to concrete tile. Also because it is important that concrete tile has to ensure the surface moisture stability, for solving the problems aplied curing method is air-dried and autoclave curing. As the result, the physical properties, such as fluent properties, compressive strength, surface hardness and surface glossiness, were decreased with increase of replacement ratio of waste concrete powder, also surface stability was weaked about moisture. But by autoclave curing, it is possible that compressive strength and surface hardness increased, and surface moisture stability is ensured.

  • PDF

Physical, Mechanical Properties and Freezing and Thawing Resistance of Non-Cement Porous Vegetation Concrete Using Non-Sintering Inorganic Binder (비소성 무기결합재를 사용한 무시멘트 다공성 식생콘크리트의 물리·역학적 특성 및 동결융해저항성 평가)

  • Kim, Hwang Hee;Kim, Chun Soo;Jeon, Ji Hong;Park, Chan Gi
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.56 no.5
    • /
    • pp.37-44
    • /
    • 2014
  • The physical, mechanical and freezing and thawing properties of non cement porous vegetation concrete using non-sintering inorganic binder have been evaluated in this study. Four types of porous vegetation concrete according to the binder type is evaluated. The pH value, void ratio, compressive strength, repeated freezing and thawing properties were tested. The test results indicate that the physical, mechanical and repeated freezing and thawing properties of porous vegetation concrete using the non-sintering inorganic binder is increased or equivalent compared to the porous vegetation concrete using the blast furnace slag + cement and hwang-toh + cement binders. Also, Vegetation monitoring test results indicate the porous vegetation concrete using the non-sintering inorganic binder have increasing effects of vegetation growth.

The properties of hydrophobic concrete prepared by biomimetic mineralization method

  • Huang, Chung-Ho;Fang, Hao-Yu;Zhang, Jue-Zhong
    • Computers and Concrete
    • /
    • v.23 no.5
    • /
    • pp.351-359
    • /
    • 2019
  • In this study, the calcium hydroxide, an inherent product of cement hydration, was treated using biomimetic carbonation method of incorporating stearic acid to generate the hydrophobic calcium carbonate on concrete surface. Carbonation reaction was carried out at various CO2 pressure and temperatures and utilizing the Scanning Electron Microscope (SEM), chloride-ion penetration test apparatus, and compression test machine to investigate the hydrophobicity, durability, and mechanical properties of the synthesized products. Experimental results indicate that the calcium stearate may change the surface property of concrete from hydrophilicity to hydrophobicity. Increasing reaction temperature can change the particles from irregular shapes to needle-rod structures with increased shear stress and thus favorable to hydrophobicity and microhardness. The contact angle against water for the concrete surface was found to increase with increasing CO2 pressure and temperature, and reached to an optimum value at around 90C. The maximum static water contact angle of 128.7 degree was obtained at the CO2 pressure of 2 atm and temperature of $90^{\circ}C$. It was also found that biomimetic carbonation increased the permeability, acid resistance and chloride-ion permeability of the concrete material. These unique results demonstrate that the needle-rod structures of CaCO3 synthetized on concrete surface could enhance hydrophobicity, durability, and mechanical properties of concrete.

An Experimental Study on The Effect of Mixed Sand Used Sea and River Sand as Fine Aggregate of Concrete (해사와 강모래의 혼합재를 사용한 콘크리트에 관한 실험적 연구)

  • 남상일;김문한;김무한
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1992.10a
    • /
    • pp.31-36
    • /
    • 1992
  • This paper, an experimental study on the effect of mixed sand used sea and river as fine aggregate of concrete, is connected with the properties of fresh and hardended concrete and steel corrosion to investigate workability and engineering properties and general steel bar's corrosion of concrete used mixed sand. After analyzing positively fresh and hardenend concrete and ratio of the corrosion area affected by the autoclave cycle, the purpose of this paper is to provide an experimental data developing concrete used mixed sand.

  • PDF

Mechanical and durability of geopolymer concrete containing fibers and recycled aggregate

  • Abdelaziz Yousuf, Mohamed;Orhan, Canpolat;Mukhallad M., Al-Mashhadani
    • Computers and Concrete
    • /
    • v.30 no.6
    • /
    • pp.421-432
    • /
    • 2022
  • Recently, the interminable ozone depletion and the global warming concerns has led to construction industries to seek for construction materials which are eco-friendly. Regarding this, Geopolymer Concrete (GPC) is getting great interest from researchers and scientists, since it can operate by-product waste to replace cement which can lead to the reduction of greenhouse gas emission through its production. Also, compared to ordinary concrete, geopolymer concrete belongs improved mechanical and durability properties. In spite of its positive properties, the practical use of geopolymer concrete is currently limited. This is primarily owing to the scarce structural, design and application knowledge. This study investigates the Mechanical and Durability of Geopolymer Concrete Containing Fibers and Recycled Aggregate. Mixtures of elastoplastic fiber reinforced geopolymer concrete with partial replacement of recycled coarse aggregate in different proportions of 10, 20, 30, and 40% with natural aggregate were fabricated. On the other hand, geopolymer concrete of 100% natural aggregate was prepared as a control specimen. To consider both strength and durability properties and to evaluate the combined effect of recycled coarse aggregate and elastoplastic fiber, an elastoplastic fiber with the ratio of 0.4% and 0.8% were incorporated. The highest compressive strength achieved was 35 MPa when the incorporation of recycled aggregates was 10% with the inclusion of 0.4% elastoplastic fiber. From the result, it was noticed that incorporation of 10% recycled aggregate with 0.8% of the elastoplastic fiber is the perfect combination that can give a GPC having enhanced tensile strength. When specimens exposed to freezing-thawing condition, the physical appearance, compressive strength, weight loss, and ultrasonic pulse velocity of the samples was investigated. In general, all specimens tested performed resistance to freezing thawing. the obtained results indicated that combination of recycled aggregate and elastoplastic fiber up to some extent could be achieved a geopolymer concrete that can replace conventional concrete.

Enhancing mechanical and durability properties of geopolymer concrete with mineral admixture

  • Jindal, Bharat Bhushan;Singhal, Dhirendra;Sharma, Sanjay;Parveen, Parveen
    • Computers and Concrete
    • /
    • v.21 no.3
    • /
    • pp.345-353
    • /
    • 2018
  • This paper approaches to improve the mechanical and durability properties of low calcium fly ash geopolymer concrete with the addition of Alccofine as a mineral admixture. The mechanical and durability performance of GPC was assessed by means of compressive strength, flexural strength, permeability, water absorption and permeable voids tests. The correlation between compressive strength and flexural strength, depth of water penetration and percentage permeable voids are also reported. Test results show that addition of Alccofine significantly improves the mechanical as well as permeation properties of low calcium fly ash geopolymer concrete. Very good correlations were noted between the depth of water penetration and compressive strength, percentage permeable voids and compressive strength as well as between compressive strength and flexural strength.