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

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.

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

2011 ◽  
Vol 194-196 ◽  
pp. 858-864 ◽  
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.

Analysis of Concrete Early-Age Shrinkage Based on the Theory of Humidity Diffusion

2011 ◽  
Vol 462-463 ◽  
pp. 183-187 ◽  
Author(s):  
Yun Feng Li ◽  
Rong Qiang Du ◽  
Fan Ying Kong
Keyword(s):  
Cement Content ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Analytical Models ◽  
Early Age ◽  
Free Shrinkage ◽  
Shrinkage Cracking ◽  
Binder Ratio ◽  
Water Binder Ratio

The early-age shrinkage cracking of concrete plays an important role to the accelerated deterioration and shortening the service life of concrete structures. Modern concretes are more sensitive to cracking immediately after setting, which is due to material characteristics (lower water/binder ratio and higher cement content) and external environmental fluctuations (humidity and temperature change). Determination of concrete free shrinkage is the basis of shrinkage cracking research. Analytical models of the autogenous shrinkage and drying shrinkage are established in this paper. The calculated results agree well with the experimental results.

scholarly journals A review on the influence of shrinkage reducing admixtures on concrete

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jerison Scariah James ◽  
Angel Rose ◽  
Elson John ◽  
Sachin Paul
Keyword(s):  
Surface Tension ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Common Source ◽  
Shrinkage Cracking ◽  
Plastic Shrinkage ◽  
Concrete Mixtures ◽  
Shrinkage Reducing Admixture ◽  
Shrinkage Reducing Admixtures ◽  
Damage In Concrete

Shrinkage cracking is a common source of distress in concrete structures. In addition to being unsightly, these cracks serve to accelerate other forms of damage in concrete, thereby shortening the service life of structures. One solution to reduce the potential for shrinkage cracking is to incorporate a shrinkage reducing admixture (SRA) in concrete mixtures. SRAs belong to a special type of organic chemicals (i.e., surfactants) that when mixed in water, reduce the surface tension of the liquid, and thereby reduce the magnitude of capillary stresses and shrinkage strains that occur when concrete is losing moisture. Various studies show that SRAs have proven to reduce drying, autogenous, and plastic shrinkage, which has been summarized in this literature. Keywords—Shrinkage Reducing Admixtures, Surfactants, Drying shrinkage, Plastic shrinkage, Autogenous shrinkage.

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

Polymers ◽  
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.

scholarly journals Effect of Shrinkage Reducing Admixture on Drying Shrinkage of Concrete with Different w/c Ratios

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5721 ◽  
Author(s):  
Mahdi Kioumarsi ◽  
Fazel Azarhomayun ◽  
Mohammad Haji ◽  
Mohammad Shekarchi
Keyword(s):  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Hardened Concrete ◽  
Free Shrinkage ◽  
Water Penetration ◽  
Concrete Shrinkage ◽  
Different Types ◽  
Shrinkage Reducing Admixture ◽  
Shrinkage Reducing Admixtures ◽  
Liquid Propylene

The reduction of the moisture content of concrete during the drying process reduces the concrete’s volume and causes it to shrink. In general, concrete shrinkage is a phenomenon that causes concrete volume to dwindle and can lead to durability problems. There are different types of this phenomenon, among them chemical shrinkage, autogenous shrinkage, drying shrinkage including free shrinkage and restrained shrinkage, and thermal contraction. Shrinkage-reducing admixtures are commercially available in different forms. The present study investigates the effect of liquid propylene glycol ether on mechanical properties and free shrinkage induced by drying at different water-cement (w/c) ratios. Furthermore, the effect of shrinkage-reducing admixtures on the properties of hardened concrete such as compressive and tensile strength, electrical resistivity, modulus of elasticity, free drying shrinkage, water absorption, and depth of water penetration was investigated. The results indicated that shrinkage reducing agents performed better in a low w/c ratio and resulted in up to 50% shrinkage reduction, which was due to the surface reduction of capillary pores. The prediction of free shrinkage due to drying was also performed using an artificial neural network.

Experimental Study on the Impact of Admixture for Concrete Heat of Hydration and Early-Age Contractile Properties

2012 ◽  
Vol 253-255 ◽  
pp. 385-389 ◽  
Author(s):  
Jian Cheng Sun ◽  
Bo Jun Wang ◽  
Wen Zhong Zhao
Keyword(s):  
Experimental Study ◽  
Fly Ash ◽  
Concrete Structure ◽  
Autogenous Shrinkage ◽  
Heat Of Hydration ◽  
Reducing Agent ◽  
Hydration Heat ◽  
Early Age ◽  
Mix Proportion ◽  
Structure Crack

During the technology development of modem concrete, concrete structure crack (especially early-age crack) becomes more and more serious and has been one of main research directions of civil engineering. This paper aims at the seriousness of concrete structure crack and presents one of main cause is that concrete early-age (especially autogenous shrinkage) become large through the experimental study. autogenous shrinkage are mainly belongs to temperature cracks and desiccation cracks. Analyses the affection of ash and water reducing agent on the hydration heat, under the optimum proportion experiment which aims at reducing he hydration heat of cement. The best program are obtained that double mix with 20% fly ash and 1.5% water reducing agent .Design mortar’s early anti-crack experiment, and study crack-resistance and other mechanical properties based on different ages & different mix proportion. From the experiment, analyses early cracking under the influence of admixtures. The mix proportion of 20% fly ash, 10% slag and 1.2% water reducing agent can minimize the creation of cracks.

Shrinkage Properties of Cement-Silica Fume Blended Pastes in Early Age

2017 ◽  
Vol 726 ◽  
pp. 521-526
Author(s):  
Di Zou ◽  
Lian Zhen Xiao ◽  
Wen Chong Shi
Keyword(s):  
Silica Fume ◽  
Rapid Growth ◽  
High Performance ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Early Age ◽  
Shrinkage Ratio ◽  
Study Results ◽  
Expansion Period

The cement-silica fume blended pastes were prepared with different silica fume (SF) dosages of 0%, 5%, 10%, and 15% at different water-binder ratios (W/B) of 0.4 and 0.5. The autogenous shrinkage (AS) and the drying shrinkage (DS) of the paste samples in the hydration period of 7d (168 hours) were measured by a new measurement technique to explore the influence of W/B and silica fume incorporation on the shrinkage in early age. The study results can provide reference for high performance concrete mix design.It is found that ether the AS or the DS of the paste samples shows a similar pattern, and the AS development with hydration time appeared a temporary expansion period after a rapid growth, especially in the samples at a higher W/B or with a lower SF content. However, the DS development did not occur obvious expansion period.Three development trends were obtained for the factors of W/B and SF content. 1) the AS and DS of the pastes mainly occurred in early ages. The lower W/B, the shorter the rapid growth periods, and the higher the shrinkage ratio of 1d to 7d. For the pastes with W/B of 0.4, the AS grew rapidly in 1d and the DS grew rapidly in the first 10h, and the AS value in 1d reached to 63.6% of 7d, and the DS value reached to 62.1% of 7d in the paste with SF of 10%. For the pastes with W/B of 0.5, the rapid growth periods of the AS and DS respectively extended to 30~33h and 12h, and the AS value in 1d reached to 60.0% of 7d, and the DS value reached to 57.2% of 7d in the paste with SF of 10%. 2) The lower W/B, the higher the shrinkage ratio of the AS to the DS. When the SF dosage is 10%, the ratio of the AS value to the DS value of 7d is 21.66%~21.15% for W/B of 0.4, and only 6.06%~5.78% for the W/B of 0.5. 3) the higher SF content results in the higher AS in cement-SF blended pastes. For the pastes with W/B of 0.4, the ratio of the AS to the DS increased from 6.98% to 30.16% with the increase of content of SF from 5% to 15% in 1d, from 15.1% to 28.19% in 3d, from 16.78% to 26.16% in 7d.

scholarly journals Studies on the Influence of Drying Shrinkage Test Procedure, Specimen Geometry, and Boundary Conditions on Free Shrinkage

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Bruce Menu ◽  
Marc Jolin ◽  
Benoit Bissonnette
Keyword(s):  
Boundary Conditions ◽  
Test Procedure ◽  
Drying Shrinkage ◽  
Experimental Results ◽  
Specimen Geometry ◽  
Ring Test ◽  
Test Results ◽  
Free Shrinkage ◽  
Free Ring ◽  
The Impact

Although considerable progress has been made in enhancing the use and interpretation of free ring shrinkage test, little is known about the impact of the test procedure, the specimen geometry, the surface area-to-volume (S/V) ratio exposed to drying, and the boundary conditions (sealing configuration) on the measured shrinkage. This paper highlights recent findings illustrating the influence of the test procedure, the S/V ratio exposed to drying, the geometry of specimen, and the boundary conditions. A series of experimental results are presented from free shrinkage on ring test specimens to illustrate that the test procedure can significantly influence the measured free shrinkage. A second series of experimental results are presented from specimens with different geometries and S/V ratio exposed to drying to illustrate that drying shrinkage is dependent on both the specimen geometry and the surface exposed to drying. Test results further show that, even for the same S/V ratio exposed to drying, shrinkage is strongly dependent on the specimen’s geometry and boundary conditions.

Study on Utilization of Silica-Calcium Tailings in Concrete

2014 ◽  
Vol 599 ◽  
pp. 93-97
Author(s):  
Xiao Wu Tian ◽  
Wei Guo Shen ◽  
Lai Shan ◽  
Liang Hong Cao ◽  
Qing Lan ◽  
...  
Keyword(s):  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Particle Morphology ◽  
Cementitious Materials ◽  
Early Age ◽  
Fine Aggregate ◽  
Safety Hazard ◽  
Total Shrinkage ◽  
Potential Safety ◽  
Large Production

The large production of tailings has caused soil, water and air pollution and serious potential safety hazard. The composition, particle morphology, particle size distribution of the silica-calcium tailings are investigated to assess the feasibility of using it in concrete in this paper. The silica-calcium tailings are mainly composed of quartz, calcite and dolomite. The results show that the tailings powder can stimulate the hydration of cement and fill the gradation gap between fine aggregate and cementitious materials in concrete as micronized sand to meet the requirements of concrete. The incorporation of silica-calcium tailings in concrete reduces the ultimate total shrinkage, autogenous shrinkage and drying shrinkage at early age.

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