Shrinkage behavior of self-compacting concrete

Journal of Building Engineering, 2017

Self-compacting concrete (SCC) is a concrete type that does not require vibration for placing and compacting. SCC possesses special technical features and properties that recommend its application in many jobs. Nevertheless, in some situations, it has been observed an inadequate behavior of the material at early ages due to shrinkage. The existing shrinkage prediction models were developed for standard concrete. In this paper three SCC mixtures, with different compressive strength, are studied in terms of autogenous and total shrinkage. The results are compared with the Eurocode 2 model. For the studied mixtures it was found that this model underestimates the autogenous shrinkage, while the total shrinkage is generally overestimated.

By means of concrete equivalent mortar (CEM) principle, concrete properties can be experimentally studied at mortar level. Based on this principle, this paper studies the influence of mix design parameters on autogenous and drying shrinkage of self-compacting concrete by means of experiments at mortar level. Mix design parameters of this study are W/C (water/cement) ratio and A/C (limestone filler /cement) ratio. The results show that autogenous shrinkage is increases with decreasing W/C and A/C ratios contrary to drying shrinkage which increases with higher ratios. Furthermore, based on mortar and paste results, it is shown that the model developed by Le Roy to predict the shrinkage of CEM and possibly of SCC, from shrinkage measured on cementing paste, is also valid for shrinkage of limestone filler based self-compacting cementitious materials. Furthermore, some known results on the influence of water/cement ratio and filler/cement ratio have been confirmed and can be explained by...

Materials and Structures, 2011

Shrinkage behavior of self-compacting concrete (SCC) can be different from that of traditional vibrated concrete, because of different paste and aggregate volumes. For traditional concrete, shrinkage can be estimated based on shrinkage results obtained on paste level. Based on homogenization techniques, Le Roy developed a model relating the shrinkage of concrete to the shrinkage of the representative cement paste, considering a granular coefficient taking into account the elastic properties and the concentration of the aggregates. By means of an extended experimental program, the applicability of this model to the case of SCC has been verified. Furthermore, some known results on the influence of water/cement ratio and filler/cement ratio have been confirmed and can be explained by porosity results.

2011

Proper estimate of autogenous shrinkage of self-consolidating concrete (SCC) can provide engineers with the information necessary for producing high quality products manufactured with SCC. An experimental program was undertaken to evaluate autogenous shrinkage of precast, prestressed SCC. Sixteen SCC with slump flow of 680 ± 20 mm were evaluated. These mixtures were made with 440 to 500 kg/m 3 of binder, Type MS cement or HE cement and 20% Class F fly ash, 0.34 to 0.40 w/cm, viscosity-modifying admixture content of 0 to 100 mL/100 kg of binder, and 0.46 to 0.54 sand-to-total aggregate volume ratio. Two high-performance concretes (HPC) with 0.34 and 0.38 w/cm and slump of 150 mm were also investigated. HPC developed similar autogenous shrinkage at 56 days compared to SCC made of a given binder type. Shrinkage was compared to prediction models proposed by Tawaza and Miyazawa 1997. The Tazawa and Miyazawa model was modified to provide adequate prediction of autogenous shrinkage for precast, prestressed SCC.

IOP Conference Series: Materials Science and Engineering, 2017

The difference between self compacting concrete (SCC) and conventional concrete (CC) is in fresh state, is the high fluidity at first and the need for vibration at second, but in hardened state, both concretes must comply with the resistance specified, in addition to securing the safety and functionality for which it was designed. This article describes the tests and results for shrinkage and creep at some medium strength Self Compacting Concrete with added sand (SCC-MSs) and two types of cement. The research was conducted at the Laboratorio de Tecnología de Estructuras (LTE) of the Universitat Politécnica de Catalunya (UPC), in dosages of 200 liters; with the idea of evaluating the effectiveness of implementation of these new concretes at elements designed with conventional concrete (CCs).

In the present paper reviewon creep and shrinkage of high-strength self-compacting concrete and experimental measurement of creep and shrinkage of HSC and HSSCC gets affected by local construction material and under Indian environmental conditions. To Studies, time-dependent deformations are very important because of the volatility of the creep and shrinkage properties and the need for better-developed models that can account for concretes containing mineral additives. These phenomena are very important in concrete design and cannot be ignored. This is especially true for typical concretes since very limited creep and Shrinkage tests were performed and therefore empirical data is scarce for the Indian Scenario.

Structural Concrete, 2020

Self-compacting concrete (SCC) is a concrete that does not require vibration for casting and consolidation. It is able to flow under its own weight, completely filling the formwork and achieving full consolidation, even in the presence of congested reinforcement. SCC possesses special technical features and properties that recommend its application in a considerable amount of applications. Nevertheless, an inadequate behavior of the material at early ages has been observed in some situations, due to shrinkage. Shrinkage has a significant importance in the design, construction and in-service performance of concrete structures. The regulatory requirements were derived from experience with traditional concrete, which is not always suitable for SCC. In addition, the option of using new materials, such as binders with large amount of pozzolanic or latent hydraulic additions, strongly limits the validity of existing rules. In order to contribute for a better understanding of the major drawback of this material-its high potential shrinkage, experimental research was carried out using different commercial shrinkage-compensating products. This study focuses on the use of a shrinkage reducing admixture and an expansive agent. The results obtained demonstrate the efficiency of the individual or combined use of these products and allowed identifying three different strategies to control the shrinkage, with distinct levels of efficiency.

Magazine of Concrete Research

In the present paper, a numerical and experimental study about creep and shrinkage behavior of a high strength self-compacting concrete is performed. Two new creep and shrinkage prediction models based on the comprehensive analysis on the available models of both conventional concrete and self-compacting concrete are proposed for high strength self-compacting concrete structures. In order to evaluate the predictability of the proposed models, an experimental program was carried out. A concrete which develops 60 MPa within 24 h was used to obtain experimental results. Several specimens were loaded: (i) at different ages and (ii) with different stress-to-strength ratios. Deformation in non-loaded specimens was also measured to assess shrinkage. All specimens were kept under constant stress during at least 600 days in a climatic chamber with temperature and relative humidity of 208C and 50%, respectively. Results showed that the new models were able to predict deformations with good ac...

2013

In the present paper, the results of an experimental campaign concerning the long-term behavior of hardened self-compacting concrete are presented. Five mixes of self-compacting concrete and one mix of conventional vibrated concrete have been employed, with different compressive strength. Strength levels have been selected to cover the range of application from cast-in-place to prestressed structures. For each mix, shrinkage and creep tests at two different ages at loading (7 and 28 days) have been performed for a period of about one year. Finally, experimental data both in terms of shrinkage and creep are compared with international code provisions. An apparent underestimation has been observed in all cases but MC2010 in predicting SCC creep behavior, where an over-prediction has been obtained. In general, the introduction inside models of the dependency from specific mix parameters seems to be advisable when considering SCCs.

2011

Shrinkage can be critical factor for the design of structural members due to the length changes by the timedependent deformation. Given the high fluidity and different mixture proportions of SCC, the shrinkage of such concrete can differ from those of conventional concrete or HPC of normal consistency. Proper estimate of autogenous shrinkage of self-consolidating concrete (SCC) can provide engineers with the information necessary for producing high quality products manufactured with SCC. An experimental program was undertaken to evaluate autogenous shrinkage of precast, prestressed SCC. Sixteen SCC with slump flow of 680 ± 20 mm were evaluated. These mixtures were made with 440 to 500 kg/m 3 of binder, Type MS cement or HE cement and 20% Class F fly ash, 0.34 to 0.40 w/cm, viscosity-modifying admixture content of 0 to 100 mL/100 kg of binder, and 0.46 to 0.54 sand-to-total aggregate volume ratio. Two highperformance concretes (HPC) with 0.34 and 0.38 w/cm and slump of 150 mm were also investigated. Based on the test results, the HPC developed similar autogenous shrinkage at 56 days compared to SCC made of a given binder type. Shrinkage was compared to prediction models proposed by Tawaza and Miyazawa 1997. The Tazawa and Miyazawa model was modified to provide adequate prediction of autogenous shrinkage for precast, prestressed SCC.