The Effect of Adding Fibers on Dry Shrinkage of Geopolymer Concrete

Despite their drastically different chemical ingredients and interactions, geopolymer concrete exhibits many of the same features as ordinary concrete. Among these properties is drying shrinkage. As in normal concrete, dry shrinkage in geopolymer concrete may cause cracking if the geopolymer concrete is bound, which affects the integrity of the structure in the future. It's important to measure drying shrinkage as soon as possible because it's the cause of early age cracking, which happens when the concrete isn't very strong. The purpose of this study is to determine how to reduce the dry shrinkage value of geopolymer concrete by using different types of fibers. Three types of fibers were used to determine their effect on the dry shrinkage of geopolymer concrete when compared with a reference mixture without the fibers. Metakaolin was used as a binder for the concrete geopolymer. As for the fibers, steel, carbon and polypropylene fibers were used in proportions of (0, 0.5, and 1%). The results showed an improvement in dryness shrinkage when adding fibers in general, with a difference in values between the different types of fibers. Steel fibers had the lowest amount of dry shrinkage. The temperature had a direct influence on the decrease in the extent of the shrinking, since the samples handled at higher temperatures had less dryness to begin with. Doi: 10.28991/cej-2021-03091780 Full Text: PDF

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Experimental Research on Ceramsite Concrete Beams

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.166-169.708 ◽

2012 ◽

Vol 166-169 ◽

pp. 708-711

Author(s):

Chuang Du ◽

Wen Ling Tian ◽

Xiao Wei Wang ◽

De Jun Wang

Keyword(s):

Concrete Beam ◽

Ultimate Load ◽

Concrete Beams ◽

Polypropylene Fiber ◽

Flexural Behavior ◽

Polypropylene Fibers ◽

Test Results ◽

Normal Concrete ◽

Ordinary Concrete ◽

Cover Thickness

Six specimens, including 4 ceramsite concrete beams(one of beams mixed into the polypropylene fiber ) and 2 normal concrete beams, were tested to investigate the flexural behavior. The test results show that cracking load of ceramsite concrete beams is slightly smaller than the ordinary concrete beam and cracking load of ceramsite concrete beams has significantly improved after mixing into the polypropylene fibers. The ultimate load of ceramsite concrete beams are no less than ordinary concrete beam,and fibers have not effects on the increase of ultimate load. Load-deflection curves were compared,and the results show that stiffness of ceramsite concrete beam is less than ordinary concrete beam. Ductility of ceramsite concrete beam is poorer than ordinary concrete beam. Fibers improve the stiffness of ceramsite concrete beam. Cover thickness of concrete beam has little effect on the performance of ceramsite concrete beam.

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Restrained Stress Development in Hardening Mortar Internally Cured with Superabsorbent Polymers under Autogenous and Drying Conditions

Polymers ◽

10.3390/polym13060979 ◽

2021 ◽

Vol 13 (6) ◽

pp. 979

Author(s):

Jung Heum Yeon

Keyword(s):

Autogenous Shrinkage ◽

Drying Shrinkage ◽

Early Age ◽

Shrinkage Cracking ◽

Stress Development ◽

Cracking Potential ◽

Different Types ◽

Internal Relative Humidity ◽

Series Of Experiments ◽

Drying Conditions

This study reports the results of a series of experiments, particularly paying attention to the early-age behavior and response of hardening mortars incorporating different types and contents of superabsorbent polymer (SAP) under autogenous (sealed) and drying shrinkage (unsealed) conditions. To achieve this primary aim, the effects of SAP type (i.e., cross-linking density and grain size) and content on the internal relative humidity (IRH) changes and corresponding free shrinkage behavior, restrained stress development, and cracking potential of the mortar were extensively measured and analyzed, along with their strength and set time properties. The results of this study have shown that the internal curing (IC) via SAP effectively counteracted the early-age residual stress build-up due to autogenous shrinkage, as many other former studies described. No or little tensile residual stresses due to autogenous shrinkage took place when more than 0.4% SAP was added, regardless of the SAP type. However, it should be mentioned that the addition of SAP, irrespective of its content and type, hardly improved the shrinkage cracking resistance of the mortar when directly exposed to drying environment at early ages.

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Influence of compressive strength and maturity conditions on shrinkage of ordinary concrete

Advances in Mechanical Engineering ◽

10.1177/16878140211024434 ◽

2021 ◽

Vol 13 (6) ◽

pp. 168781402110244

Author(s):

Olga Szlachetka ◽

Joanna Witkowska-Dobrev ◽

Marek Dohojda ◽

Anna Cała

Keyword(s):

Compressive Strength ◽

Portland Cement ◽

Drying Shrinkage ◽

Point Of View ◽

Early Age ◽

Volume Changes ◽

Ordinary Concrete ◽

Dry Conditions ◽

Total Elimination

The paper presents results of investigations of compressive strength and shrinkage of concrete samples made on the basis of the Portland cement CEM I 32.5R, after 2, 7, 14, 28, 90, and 365 days of maturation in four different maturation conditions. It was shown that after 28 days the samples cured according to the standard in the cuvettes with water achieved the highest compressive strength, although the early-age compressive strengths after 7 and 14 days were lower than those for the samples cured in building film and in dry conditions. A determined correlation between the compressive strength and shrinkage of the concrete proves that wet curing also allows a total elimination of the shrinkage in the first 28 days. Along with the growth of the compressive strength, the drying shrinkage reduces. Obtained results confirmed that the best way of concrete curing, among the analyzed methods, from the point of view of both compressive strength and volume changes is the wet curing.

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Experimental Study on the Early Shrinkage-cracking Property of the Polypropylene Fibe Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.236-238.2259 ◽

2011 ◽

Vol 236-238 ◽

pp. 2259-2263

Author(s):

Xian Song Xie

Keyword(s):

Experimental Study ◽

Autogenous Shrinkage ◽

Drying Shrinkage ◽

Early Age ◽

Polypropylene Fibers ◽

Free Shrinkage ◽

Shrinkage Cracking ◽

Plastic Shrinkage ◽

Hardening Process ◽

The Impact

Early shrinkage of concrete includes plastic shrinkage before the final setting, drying shrinkage during hardening process and autogenous shrinkage. Concrete drying shrinkage which is caused by evaporation is a major factor for the concrete volume change. By ring constrained test and free shrinkage CONCEN test, this paper studies the impact of polypropylene fibers on the shrinkage properties of concrete at the early age. The test shows that the polypropylene fibers can significantly reduce the early shrinkage of concrete, the best content of C30 concrete should be 0.9kg/m3.

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Properties of Cracking Resistance of Cemfiber Reinforced Concrete

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.280-283.1765 ◽

2007 ◽

Vol 280-283 ◽

pp. 1765-1770 ◽

Cited By ~ 2

Author(s):

Feng Xing ◽

Fa Guang Leng ◽

Wei Wen Li

Keyword(s):

Tensile Strength ◽

High Performance ◽

High Performance Concrete ◽

Polypropylene Fiber ◽

Shrinkage Strain ◽

Early Age ◽

Polypropylene Fibers ◽

Cracking Resistance ◽

Ordinary Concrete ◽

Concrete Form

Polypropylene fiber is a new measure to prevent plastic cracks of concrete. Effects of the parameters, such as dosage and types of fibers, on the plastic cracks were studied systematically. The properties of cracking resistance of mortar, ordinary concrete and high performance concrete were investigated by using samples of two types in shape. The results show that: (1) polypropylene fibers may increase the cracking resistance of concrete further; (2) as smaller quantity of cement and higher quantity of aggregate as possible should be used to prevent concrete form cracking; (3) the main reason why polypropylene fibers increase cracking resistance of concrete is that they increase strain capacity of concrete at early age, decrease shrinkage strain, improve plastic tensile strength and decrease tensile stress of the capillary.

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Mechanical Properties of Hybrid Structures Incorporating Nano-Silica and Basalt Fiber Pellets

CivilEng ◽

10.3390/civileng2040049 ◽

2021 ◽

Vol 2 (4) ◽

pp. 909-928

Author(s):

Ahmed Bediwy ◽

Ehab F. El-Salakawy

Keyword(s):

Basalt Fiber ◽

Steel Fibers ◽

Layered Composites ◽

Cementitious Composite ◽

Nano Silica ◽

Normal Concrete ◽

Free System ◽

Cracking Behavior ◽

Different Types ◽

Analysis Of Results

Recently, developing a nonferrous reinforcement system (corrosion-free system) using durable and ductile cement-based materials that incorporate discrete fibers has been a promising option for exposed concrete structures in cold regions or marine environments. Therefore, in this study, properties of a novel type of cementitious composite comprising nano-silica and a high dosage of slag were investigated. The hybrid (layered) composites assessed in this study were composed of two layers of different types of cementitious composites. Normal concrete (NC) was used in the top layer combined with a layer of fiber-reinforced cementitious composite (FRCC) reinforced with either the recently developed basalt fiber (BF) pellets (basalt fiber strands encapsulated by a polymeric resin or steel fibers (SF)) that were used at different dosages. The post-cracking behavior in terms of residual strength, residual index, and toughness are presented and discussed. The analysis of results showed the effectiveness of the BF pellets in enhancing the post-cracking behavior of specimens, as they behaved comparably to counterpart specimens comprising SF, which makes them a good candidate for infrastructural applications including rehabilitation such as new bridge girders or overlays.

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Analysis of Abrasion Depth and Rates in Concrete

Modern Applied Science ◽

10.5539/mas.v15n6p1 ◽

2021 ◽

Vol 15 (6) ◽

pp. 1

Author(s):

Mohammed Saleh AlAnsari

Keyword(s):

Comparative Analysis ◽

High Performance ◽

High Performance Concrete ◽

Fiber Reinforced Concrete ◽

Steel Fibers ◽

Hydraulic Structures ◽

Polypropylene Fibers ◽

New Techniques ◽

Different Types ◽

High Performance Fiber

Abrasion is a major problem in hydraulic structures as they are continuously exposed to various types of water. Henceforth, these structures are susceptible to damage and require heavy maintenance. There is a significant demand in finding new techniques for improving the resistance towards the erosion of the concrete used in the construction of hydraulic structures. This work put forth a comparative analysis of the performance of two different types of concretes towards resistance namely, high-performance fiber reinforced concrete (HPFRC) [steel fibers (30 mm and 50 mm) and polypropylene fibers (19 mm)] and high-performance concrete (HPC). A comparative study was carried out based on their resistance towards wearing and hydro-abrasion erosion. The analyses were conducted using the WMP ECLIPSE method and ASTM C 1138 method. The results indicated that the rate of abrasion could be diminished by 18% based on the types of cement, fibers, concrete and modifications like the addition of silica fume. 

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Experimental Investigation into the Impact of Polypropylene Fibers and SRA on the Early Crack Resistance of Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.194-196.858 ◽

2011 ◽

Vol 194-196 ◽

pp. 858-864 ◽

Cited By ~ 1

Author(s):

Xian Song Xie ◽

Fang Tian ◽

Yi Hong Hong

Keyword(s):

Experimental Investigation ◽

Volume Change ◽

Autogenous Shrinkage ◽

Drying Shrinkage ◽

Early Age ◽

Polypropylene Fibers ◽

Free Shrinkage ◽

Plastic Shrinkage ◽

Hardening Process ◽

The Impact

Early shrinkage of concrete includes plastic shrinkage before the final setting, drying shrinkage during hardening process and autogenous shrinkage. Concrete drying shrinkage which is caused by evaporation is a major factor for the concrete volume change. By ring constrained test and free shrinkage TONCEN test, this paper studies the impact of polypropylene fibers and SRA on the shrinkage properties of concrete at the early age. The test shows that the polypropylene fibers and SRA can significantly reduce the early shrinkage of concrete, and SRA works more evidently than polypropylene fibers.

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Compressive Strength Properties of Fly Ash-Based Geopolymer Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.741.49 ◽

2013 ◽

Vol 741 ◽

pp. 49-54 ◽

Cited By ~ 1

Author(s):

Gum Sung Ryu ◽

Gi Hong Ahn ◽

Kyung Taek Koh ◽

Jang Hwa Lee

Keyword(s):

Compressive Strength ◽

Elastic Modulus ◽

Fly Ash ◽

Ordinary Portland Cement ◽

Mechanical Characteristics ◽

Strength Properties ◽

Early Age ◽

Geopolymer Concrete ◽

Test Results ◽

Ordinary Concrete

This study intends to investigate experimentally the mechanical characteristics of the compressive strength and elastic modulus of concrete using 3 types of binder that are ordinary Portland cement, fly ash and physically milled fly ash. The test results show that the compressive strength and elastic modulus of the cement-zero concrete reached respectively 30.0 MPa and 19.1 GPa, and indicated that more than 90% of the strength was developed at early age. In addition, a comparison of the geopolymer concrete with ordinary concrete enabled to derive and suggest formulaeexpressing the elastic modulus in function of the compressive strength.

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