scholarly journals The effect of shrinkage reducing admixtures on drying shrinkage, autogenous deformation, and early age stress development of concrete

2020 ◽  
Author(s):  
Anja Estensen Klausen ◽  
Terje Kanstad
Keyword(s):  
Drying Shrinkage ◽  
Early Age ◽  
Stress Development ◽  
Autogenous Deformation ◽  
Shrinkage Reducing Admixtures

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.

Instrumentation and Analysis of High-Performance Concrete Bridge Decks

2005 ◽  
Vol 1914 (1) ◽  
pp. 85-96 ◽  
Author(s):  
Matthew D. D'Ambrosia ◽  
David A. Lange ◽  
Zachary C. Grasley ◽  
Jeffery R. Roesler ◽  
Chang Joon Lee ◽  
...  
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Bridge Decks ◽  
Drying Shrinkage ◽  
Field Investigation ◽  
Thermal Shrinkage ◽  
Early Age ◽  
Concrete Bridge ◽  
Stress Development ◽  
Concrete Bridge Decks

The use of high-performance concrete (HPC) for transportation structures was the subject of a 3-year study that involved field investigation, laboratory experiments, analysis, and modeling. The field study involved instrumentation and analysis of six HPC bridge decks. The laboratory component characterized early-age thermal, shrinkage, creep, and cracking behaviors. A three-dimensional finite element model was used in conjunction with material models to analyze and predict creep and shrinkage behavior and to investigate structural and material interactions. This paper focuses on the field component of the project and discusses the instrumentation, deformation measurements, and analysis of bridge decks in Illinois. The bridges were instrumented to understand the development of shrinkage and thermal stress in concrete bridge decks with the use of various materials and structural components. The results indicate that the stress development due to daily temperature cycles and long-term temperature changes are relatively small compared with the stress development due to drying shrinkage. According to model simulations, a 15% to 40% reduction in shrinkage would reduce the stress level enough to prevent most cracking. Although drying shrinkage is the major driving force for stress development, the interaction of concrete shrinkage and structural restraint influences the magnitude of the stress and is linked to the propensity for early-age cracking.

Control of Cracking with Shrinkage-Reducing Admixtures

1997 ◽  
Vol 1574 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Surendra P. Shah ◽  
Shashidhara Marikunte ◽  
Wei Yang ◽  
Corina Aldea
Keyword(s):  
Drying Shrinkage ◽  
Plain Concrete ◽  
Type Specimen ◽  
Wire Mesh ◽  
Restrained Shrinkage ◽  
Shrinkage Cracking ◽  
Restrained Shrinkage Cracking ◽  
Tensile Forces ◽  
Parking Garages ◽  
Shrinkage Reducing Admixtures

Shrinkage cracking can be a critical problem in concrete construction, especially for flat structures such as highway pavements, slabs for parking garages, and bridge decks. One way to reduce the shrinkage cracking is to provide reinforcement in the form of wire mesh to resist tensile forces. In recent years, short, randomly distributed fibers have been used to control shrinkage cracking. The efficiency of shrinkage-reducing admixtures (SRAs) in controlling restrained shrinkage cracking of concrete is reviewed. A ring-type specimen was used for restrained shrinkage cracking tests. The SRA selected for this investigation was a propylene glycol derivative, which was used at 1 and 2 percent by weight of cement. Free (unrestrained) shrinkage, weight loss, compressive strength, and fracture toughness were also investigated. The results of SRA concretes were compared with that of plain concrete with the same water-to-cement ratio. A theoretical model based on nonlinear fracture mechanics was developed for predicting transverse cracking of the concrete ring specimen caused by drying shrinkage. The model prediction of time to cracking compared well with the experimental data. The model can be extended to different geometries and dimensions than those considered in this research.

scholarly journals Numerical Modelling of Field Test for Crack Risk Assessment of Early Age Concrete Containing Fly Ash

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
G. M. Ji ◽  
T. Kanstad ◽  
Ø. Bjøntegaard
Keyword(s):  
Fly Ash ◽  
Wall Structure ◽  
Early Age ◽  
Measured Temperature ◽  
Finite Element Program ◽  
Stress Development ◽  
Thermal Dilation ◽  
Early Age Concrete ◽  
Mineral Additives ◽  
Cracking Risk

The high-strength/high-performance concretes are prone to cracking at early age due to low water/binder ratio. The replacement of cement with mineral additives such as fly ash and blast-furnace slag reduces the hydration heat during the hardening phase, but at the same time, it has significant influence on the development of mechanic and viscoelastic properties of early age concrete. Its potential benefit to minimize the cracking risk was investigated through a filed experiment carried out by the Norwegian Directorate of Roads. The temperature development and strain development of the early age concrete with/without the fly ash were measured for a “double-wall” structure. Based on experimental data and well-documented material models which were verified by calibration of restraint stress development in TSTM test, thermal-structural analysis was performed by finite element program DIANA to assess the cracking risk for concrete structures during hardening. The calculated and measured temperature and strain in the structure had good agreement, and the analysis results showed that mineral additives such as flay ash are beneficial in reducing cracking risk for young concrete. Furthermore, parameter studies were performed to investigate the influence of the two major factors: creep and volume change (autogenous shrinkage and thermal dilation) during hardening, on the stress development in the structure.

Influence of Early Age Volume Changes on Long-Term Concrete Shrinkage

1998 ◽  
Vol 1610 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Erika E. Holt ◽  
Donald J. Janssen
Keyword(s):  
Concrete Slab ◽  
Drying Shrinkage ◽  
Early Age ◽  
Volume Changes ◽  
Test Procedures ◽  
Cracking Behavior ◽  
Concrete Shrinkage ◽  
Cracking Potential ◽  
Partially Restrained

Volume changes can occur in concrete during the first 24 hr and are generally missed in laboratory shrinkage evaluations. Unfortunately these early age volume changes are present in real pavements and structures and can contribute to the cracking behavior of the concrete at later ages. Early age volume changes can occur in two forms: drying shrinkage before the start of curing and autogenous volume changes. Although these early age volume changes are often dismissed as being insignificant, recent work in Europe has identified magnitudes for early age volume changes of some concretes that are equal to or greater than 28-day drying shrinkage measurements. Expansions have also been identified in some cases. The results of some investigations of volume changes in concrete during the first 24 hr under both drying and nondrying conditions are presented. An example of potential long-term cracking under partially restrained conditions (concrete slab-on-grade modeled by a concrete ring cast around a hollow steel ring) is used to illustrate the magnitude of influence of early age volume changes on concrete cracking. Both test procedures employ nonstandard methods to quantify the cracking potential of concrete.

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.

Sign in / Sign up

Export Citation Format

Share Document