A study on creep and drying shrinkage of high performance concrete

2001 ◽  
Vol 31 (8) ◽  
pp. 1203-1206 ◽  
Author(s):  
Jianyong Li ◽  
Yan Yao
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Drying Shrinkage

EXPERIMENTAL STUDY ON DURABILITY OF ROOM TEMPERATURE CURING UFC MORTAR

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Haruka Murakami ◽  
Hiromi Fujiwara ◽  
Masanori Maruoka ◽  
Takahumi Watanabe ◽  
Koji Satori
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
High Performance ◽  
Room Temperature ◽  
Bending Strength ◽  
High Performance Concrete ◽  
Drying Shrinkage ◽  
Concrete Repair ◽  
Repair Materials ◽  
Low Salt

In recent years, as structures become higher, larger, and more durable concrete whose compressive strength of the concrete is 150 N/mm 2 or more have been put to practical use. It is for this reason that it is necessary to develop strengthening materials with equal or better performance. Furthermore, the development of high-performance concrete repair materials is carried out because demand to seismic strengthening and repair increases. In this study, considering these circumstances, it was conducted an experimental study with the aim of developing a repair material using room temperature curing UFC (R-UFC). A binder composition preparation of the R-UFC has excellent fluidity under pressure. It was achieved that high-grade thixotropy, high compressive strength, and high bending strength. It can also be sprayed continuously because of its high thixtoropy. It was confirmed that the sprayed thickness was reached to 20mm by one work. Durability of this R-UFC was investigated and it was confirmed the high sulfate resistance, small drying shrinkage and low salt permeability.

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.

Influence of CaO-Based Expansive Agent on the Deformation Behavior of High Performance Concrete

2013 ◽  
Vol 438-439 ◽  
pp. 113-116
Author(s):  
Shou Zhi Zhang ◽  
Qian Tian ◽  
An Qun Lu
Keyword(s):  
Deformation Behavior ◽  
High Performance ◽  
High Performance Concrete ◽  
Control Volume ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Volume Stability ◽  
Expansive Agent ◽  
Effective Expansion ◽  
New Type

In order to improve the volume stability of high performance concrete, the effects of deformation behavior of high performance concrete containing CaO-based expansive agent were investigated. Concrete samples prepared without or with CaO-based expansive agent were compared through expansion under water curing at 20°C, drying shrinkage and autogenous shrinkage measurements. According to the experimental and analytical results, the new type expansive agent can control volume stability for high performance concrete. The addition of 10% CaO-based expansive agent not only built effective expansion in high performance concrete whatever under saturated condition or under sealed condition, but also substantially reduced its drying shrinkage.

Chemical Shrinkage of Pastes Made with Shrinkage Reducing Admixtures

2011 ◽  
Vol 466 ◽  
pp. 105-113 ◽  
Author(s):  
António Bettencourt Ribeiro ◽  
Vasco Medina ◽  
Augusto Gomes ◽  
Arlindo Gonçalves
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Chemical Shrinkage ◽  
Cement Pastes ◽  
Degree Of Hydration ◽  
Shrinkage Cracks ◽  
Large Application ◽  
Shrinkage Reducing Admixtures

Shrinkage Reducing Admixtures (SRA) are being used more often in concrete structures in order to better control shrinkage cracks. High-performance concrete, nowadays with large application, has more proneness to crack at very early age due to the lower W/C. In this type of concrete, autogenous shrinkage is usually more important than drying shrinkage. Autogenous shrinkage is due to the volume decrease inherent to binder hydration reactions. The rate of these reactions is influenced not only by the type of binder but also by the presence of chemical admixtures. It is recognized that SRA delay the hydration, being a secondary effect of this type of admixtures. In this work changes on the degree of hydration of cement pastes with SRA and different binders are presented, using the chemical shrinkage test.

scholarly journals Synthesis of Modified Polycarboxylate and Its Application in Ultra-High Performance Concrete

2021 ◽  
Vol 8 ◽  
Author(s):  
Shuncheng Xiang ◽  
Yansheng Tan ◽  
Yingli Gao
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
Chain Transfer ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Synthesis Method ◽  
Drying Shrinkage ◽  
Polymerization Reaction ◽  
Ultra High Performance Concrete ◽  
Initiation System

Modified polyurethane prepolymer was prepared using the segmental synthesis method. Then, pectiniform polycarboxylate was synthesized at normal temperature in the complex initiation system of H2O2, APS, sodium bisulfite, Vc, and Rongalit according to the free radical polymerization reaction mechanism, using TPEG, AA, and PEG as raw materials and TGA as the chain transfer agent. Compared with commercial Sika polycarboxylate, its flowability, strength, drying shrinkage, and auto-shrinkage were studied. The experimental results show that the synthesized polycarboxylate could be better dispersed. Adding silica fume can enhance the compressive strength of ultra-high performance concrete (UHPC), while slag may decline its strength. By incorporating slag and silica fume, the drying shrinkage of UHPC was reduced, but its auto-shrinkage was increased.

Durability and Performance of Indigenous Amorphous Silica in Advanced Cementitious Systems

2007 ◽  
Vol 29-30 ◽  
pp. 375-379 ◽  
Author(s):  
A.G. Langdon ◽  
G.H. Moran ◽  
W. South
Keyword(s):  
Amorphous Silica ◽  
High Performance ◽  
High Performance Concrete ◽  
Drying Shrinkage ◽  
Chloride Diffusion ◽  
Plastic Properties ◽  
Chemical Attack ◽  
Improved Stability ◽  
Improved Performance ◽  
And Performance

Microsilica 600 (MS60) is a highly reactive pozzolan processed from a natural white geosilica deposit found in New Zealand’s Rotorua district. Like silica fume it is a very fine amorphous silica and falls into the microsilica family of products. As part of a feasibility study of using MS600 in the manufacturing process of Golden Bay Cement, this work establishes the improved performance characteristics that can be achieved with MS600 When added with Portland cement, MS600 facilitates high performance concrete by achieving: increased compressive strength, improved sulphate resistance, reduced alkali silica reactity, very low chloride diffusion, reduced water permeability, improved abrasion resistance. improved resistance to chemical attack, improved stability in geothermal environments, superior plastic properties (moderate concrete bleed, lower heat generated, high quality finish) and low drying shrinkage characteristics. It has been shown that MS600 will satisfy performance requirements in applications requiring an advanced concrete material having long serviceability in harsh environments or where structural performance beyond current limitations are pre-requisites.

Effect of Curing Methods on Early-Age and Drying Shrinkage of High-Performance Concrete

2003 ◽  
Vol 1834 (1) ◽  
pp. 48-58 ◽  
Author(s):  
Hani Nassif ◽  
Nakin Suksawang ◽  
Maqbool Mohammed
Keyword(s):  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Drying Shrinkage ◽  
Lightweight Aggregate ◽  
Analytical Models ◽  
Early Age ◽  
Curing Conditions ◽  
Curing Methods ◽  
Technical Specifications

Many engineers and agencies have observed that the field implementation of high-performance concrete (HPC) is highly dependent on curing and placing conditions. The effect of curing conditions on the early-age properties and long-term durability of HPC is not fully understood. There is a need to expand the knowledge of early-age properties and of the effect of pozzolanic material (like silica fume and fly ash) on drying shrinkage. Results are presented of a study performed to identify the effect of various curing methods on the early-age (autogenous) as well as drying shrinkage of normal and lightweight HPC. The study included a comparison of available analytical models for predicting early-age and drying shrinkage with results from tests performed on different mixes. HPC mixes were developed and evaluated as part of an overall study for the New Jersey Department of Transportation to develop and implement mix designs and technical specifications for HPC transportation structures, such as pavements and bridges. The effect of using three different curing methods on the early-age performance of HPC is presented. The curing conditions consisted of air-dry curing, burlap or moist curing, and use of a curing compound. Results show that moist (burlap) curing should be applied within 1 h after the placement of concrete to improve early-age performance. For very low water-to-cement plus pozzolan ratios, fly ash and lightweight aggregate improved the autogenous shrinkage performance. Moreover, current shrinkage models need to be revised to address HPC mixes.

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