scholarly journals EXPERIMENTAL STUDY ON INFLUENCE OF EXPANSIVE ADDITIVE AND SHRINKAGE REDUCING ADMIXTRE TO DRYING SHRINKAGE OF CONCRETE

2011 ◽  
Vol 65 (1) ◽  
pp. 233-238
Author(s):  
Yoshiaki OHNO ◽  
Yoshihiro MASUDA ◽  
Tadatsugu KAGE
Keyword(s):  
Experimental Study ◽  
Drying Shrinkage ◽  
Expansive Additive

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.

scholarly journals Effects of Sand/Fly Ash and the Water/Solid Ratio on the Mechanical Properties of Engineered Geopolymer Composite and Mix Design Optimization

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 333
Author(s):  
Muhammad Zahid ◽  
Nasir Shafiq
Keyword(s):  
Experimental Study ◽  
Fly Ash ◽  
Response Surface ◽  
Drying Shrinkage ◽  
Sand Fly ◽  
Significance Level ◽  
Solid Ratio ◽  
Geopolymer Matrix ◽  
Two Parameters ◽  
Rsm Technique

This paper presents the results of an experimental study that investigated the effects of two parameters: sand/fly ash (S/FA) ratio and water to geopolymer-solid (W/GS) ratio on the engineered geopolymer composite. The trial mix designs were optimized using the response surface method. These parameters influence the properties of the fresh and hardened geopolymer matrix, such as slump flow, compressive strength, flexural strength, elastic modulus, flexural toughness, ductility index and drying shrinkage. The optimizing process was conducted by developing statistical models using the response surface methodology (RSM) technique. The developed models were statistically validated and could be used to determine the desired response of engineered geopolymer composite (EGC) with a significance level of more than 95%. In this study, the optimized values of the S/FA ratio and W/GS ratio were obtained as 0.341701 and 0.225184, respectively. To validate the optimized S/FA ratio and W/GS ratio, an experimental study was performed, and a difference of less than 5% was found between predicted and experimental results.

Evaluation of shrinkage and cracking in concrete of ring test by acoustic emission method

2015 ◽  
Vol 29 (06n07) ◽  
pp. 1540033
Author(s):  
Takeshi Watanabe ◽  
Chikanori Hashimoto
Keyword(s):  
Acoustic Emission ◽  
Portland Cement ◽  
Drying Shrinkage ◽  
Length Change ◽  
Ring Test ◽  
Emission Method ◽  
Expansive Additive ◽  
Free Body ◽  
Lime Stone ◽  
Methods Of Measurement

Drying shrinkage of concrete is one of the typical problems related to reduce durability and defilation of concrete structures. Lime stone, expansive additive and low-heat Portland cement are used to reduce drying shrinkage in Japan. Drying shrinkage is commonly evaluated by methods of measurement for length change of mortar and concrete. In these methods, there is detected strain due to drying shrinkage of free body, although visible cracking does not occur. In this study, the ring test was employed to detect strain and age cracking of concrete. The acoustic emission (AE) method was adopted to detect micro cracking due to shrinkage. It was recognized that in concrete using lime stone, expansive additive and low-heat Portland cement are effective to decrease drying shrinkage and visible cracking. Micro cracking due to shrinkage of this concrete was detected and evaluated by the AE method.

scholarly journals Influence of expansive additive on formation of fresh polymer modified pastes

2018 ◽  
Vol 239 ◽  
pp. 01023
Author(s):  
Oksana Larsen ◽  
Marsel Nurtdinov ◽  
Viktoria Shvetsova ◽  
Ekaterina Fomina
Keyword(s):  
Structure Formation ◽  
Drying Shrinkage ◽  
Initial Mixture ◽  
Heat Evolution ◽  
Water Soluble ◽  
Strength Development ◽  
Cement Ratio ◽  
Expansive Additive ◽  
Evolution Behavior ◽  
Polymer Dispersions

Chemical admixtures are widely used in cement-based mixtures to reduce water demand, increase working time or accelerate strength development. The application of water-soluble polymers in building industry is increasing. The performance of cement mortars and concretes can be improved by the modification of their structure with additives of polymers. The use of polymers in cement-based compositions can decrease the intensity of hydration kinetic and increase the shrinkage deformation. Hardening of polymer-modified cement-based mixtures is associated with drying shrinkage which can significantly decrease crack resistance of cement concretes, especially in the case of polymer dispersions. The influence of polymer admixture with expansive additive on formation of cement-based pastes was investigated. Structure formation of fresh polymer modified cementitious mixtures with expansive additive was experimentally investigated by heat evolution behavior. Structure formation as a function of time and depends from initial mixture design properties such as water-cement ratio, polymer-cement ratio and content of expansive additive.

scholarly journals Drying shrinkage, strength and microstructure of alkali-activated high-calcium fly ash using FGD-gypsum and dolomite as expansive additive

2020 ◽  
Vol 114 ◽  
pp. 103760 ◽  
Author(s):  
Sakonwan Hanjitsuwan ◽  
Borwonrak Injorhor ◽  
Tanakorn Phoo-ngernkham ◽  
Nattapong Damrongwiriyanupap ◽  
Long-Yuan Li ◽  
...  
Keyword(s):  
Fly Ash ◽  
Drying Shrinkage ◽  
Fgd Gypsum ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Expansive Additive ◽  
Alkali Activated

scholarly journals Experimental Study on the Shrinkage Behavior and Mechanical Properties of AAM Mortar Mixed with CSA Expansive Additive

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3312 ◽  
Author(s):  
Sung Choi ◽  
Gum-Sung Ryu ◽  
Kyeong-Taek Koh ◽  
Gi-Hong An ◽  
Hyeong-Yeol Kim
Keyword(s):  
Modulus Of Elasticity ◽  
Compensation Effect ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Shrinkage Stress ◽  
Calcium Sulfoaluminate ◽  
Total Shrinkage ◽  
Expansive Additive ◽  
Shrinkage Compensation

In this study, a calcium sulfoaluminate-based expansive additive (0%, 2.5%, 5.0%, and 7.5% by the mass of the binder) was added to compensate for the shrinkage of alkali-activated material (AAM) mortar. Modulus of elasticity curves based on the ACI 209 model were derived for the AAM mortar mixed with the additive by measuring the compressive strength and modulus of elasticity. Moreover, autogenous shrinkage and total shrinkage were measured for 150 days, and drying shrinkage was calculated by excluding autogenous shrinkage from total shrinkage. For the autogenous and drying shrinkage of AAM mortar, shrinkage curves by age were obtained by deriving material constants using the exponential function model. Finally, shrinkage stress was calculated using the modulus of elasticity of the AAM mortar and the curves obtained using the shrinkage model. The results showed that the calcium sulfoaluminate-based expansive additive had an excellent compensation effect on the drying shrinkage of AAM mortar, but the effect was observed only at early ages when the modulus of elasticity was low. From a long-term perspective, the shrinkage compensation effect was low when the modulus of elasticity was high, and thus, shrinkage stress could not be reduced.

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