Long-Term Behavior of Low-Heat Cement Concrete under Different Curing Temperatures

2016 ◽  
Vol 723 ◽  
pp. 819-823 ◽  
Author(s):  
Jae Sung Mun ◽  
Keun Hyeok Yang ◽  
Si Jun Kim
Keyword(s):  
Drying Shrinkage ◽  
Curing Temperature ◽  
Limestone Powder ◽  
Partial Replacement ◽  
Mass Concrete ◽  
Test Results ◽  
Long Term Behavior ◽  
Ambient Curing ◽  
Ternary Blended Concrete

The present study is to estimate long-term characteristics of low-heat cement-based ternary blended concrete prepared for reducing hydration heat in mass concrete. 15% modified fly ash and 5% limestone powder were added for partial replacement of the low-heat cement. To achieve the designed compressive strength of 42 MPa, water-to-binder ratios were determined to be 27.5, 30 and 32.5% for ambient curing temperatures of 5, 20 and 40°C, respectively. Test results showed that, with the decrease in curing temperature, the drying shrinkage strains tended to decrease, whereas creep strain increased.

scholarly journals Effect of limestone powder on self-compacting concrete

2021 ◽  
Vol 9 (2) ◽  
pp. 71-78
Author(s):  
O. M. A. Daoud ◽  
O. S. Mahgoub
Keyword(s):  
Construction Material ◽  
Control Sample ◽  
Drying Shrinkage ◽  
Heat Of Hydration ◽  
Limestone Powder ◽  
Partial Replacement ◽  
Self Compacting Concrete ◽  
Technical Problems ◽  
Cement Replacement ◽  
Partial Cement Replacement

Self-compacting concrete (SCC) is an innovative construction material in the construction industry. It is a highly fluid and stable concrete that flows under its own weight and fills completely the formwork. The SCC requires high powder content (mainly of cement) up to 600kg/ to achieve its properties. This will be problematic because increasing the cement content is not feasible, and may cause high cost and some other technical problems such as higher heat of hydration and higher drying shrinkage. This paper investigates the effect of limestone powder (LSP) on fresh and hardened properties of SCC due to the use of LSP as a partial cement replacement. For comparison, a control sample of concrete was prepared without LSP to compare it with the various samples containing different percentages of LSP as a partial replacement of cement. Four mixes with a constant amount of (superplasticizer, sand, coarse aggregate, and water) at various replacement levels of 0%, 10%, 20% and 30% from the cement weight were prepared. The experimental results show that the LSP can be effectively used as a partial cement replacement on SCC to reduced cost and enhanced the performance of SCC in fresh and hardened stages.  

scholarly journals Effects of Mixing and Curing Temperature on the Strength Development and Pore Structure of Fly Ash Blended Mass Concrete

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Ki-Bong Park ◽  
Takafumi Noguchi
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Pore Structure ◽  
Weather Conditions ◽  
Strength Loss ◽  
Curing Temperature ◽  
Strength Development ◽  
Mass Concrete ◽  
Term Strength

The aim of this work is to know clearly the effects of temperature in response to curing condition, hydration heat, and outside weather conditions on the strength development of high-performance concrete. The concrete walls were designed using three different sizes and three different types of concrete. The experiments were conducted under typical summer and winter weather conditions. Temperature histories at different locations in the walls were recorded and the strength developments of concrete at those locations were measured. The main factors investigated that influence the strength developments of the obtained samples were the bound water contents, the hydration products, and the pore structure. Testing results indicated that the elevated summer temperatures did not affect the early-age strength gain of concrete made using ordinary Portland cement. Strength development was significantly increased at early ages in concrete made using belite-rich Portland cement or with the addition of fly ash. The elevated temperatures resulted in a long-term strength loss in both belite-rich and fly ash containing concrete. The long-term strength loss was caused by a reduction in the degree of hydration and an increase in the total porosity and amount of smaller pores in the material.

scholarly journals A Study on High Strength Concrete with Moderate Cement Content Incorporating Limestone Powder

2014 ◽  
Vol 61 (1) ◽  
pp. 43-58 ◽  
Author(s):  
Alaa M. Rashad ◽  
Hosam.El Din H. Seleem
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Coarse Aggregate ◽  
Cement Content ◽  
Drying Shrinkage ◽  
High Strength ◽  
Limestone Powder ◽  
Test Results ◽  
Strength Concrete ◽  
The Difference

Abstract This paper presents the results of an investigation to assess the validity of producing high strength concrete (HSC) using moderate cement content to reduce the consumption of the binders. Cement content is lowered from 500 kg/m3 to 400 kg/m3. The difference in cement content is compensated by the addition of fine limestone (LS) powder. Pozzolans were incorporated as an addition to cement. Different coarse aggregate types were employed. Workability, compressive strength, tensile strength, permeability and drying shrinkage were measured. Test results revealed that HSC with a compressive strength up to 79 MPa (at 90 days age) could be produced with moderate cement content. The mixtures consistency and drying shrinkage are greatly enhanced due to employing LS powder and the permeability is satisfactory. To provide better solution to some concrete disadvantages like cracking and drying shrinkage, using an economic rate for cement are believed to reduce these disadvantages.

scholarly journals Strategies for improving dimensional stability of concrete

2016 ◽  
Vol 43 (10) ◽  
pp. 875-885
Author(s):  
P.L. Ng ◽  
Albert K.H. Kwan
Keyword(s):  
Dimensional Stability ◽  
Cement Content ◽  
Drying Shrinkage ◽  
Sustained Load ◽  
Early Age ◽  
Test Results ◽  
Dimensional Changes ◽  
Shrinkage And Creep ◽  
Concrete Mix

Changes in dimension of concrete due to early-age heat generation, long-term drying shrinkage, and creep under sustained load could lead to significant movements of the concrete structure and lock-up stresses if the movements are restrained. The lock-up stresses are often large enough to cause cracking and water leakage, thereby adversely affecting the serviceability and durability of the structure. Whilst the dimensional changes are quite variable because of their dependence on the environmental conditions and applied loads, they are all related to the concrete mix proportions. Generally, the dimensional stability of concrete can be improved by reducing its cement content and paste volume. Moreover, since the aggregate also shrinks, the dimensional stability can be improved by suppressing the shrinkage of aggregate as well. In this paper, strategies for improving the dimensional stability of concrete are formulated based on experimental research. Test results are presented to demonstrate their effectiveness and applicability.

scholarly journals Use of supplementary cementitious materials (SCMs) in reinforced concrete systems – Benefits and limitations

2020 ◽  
Vol 10 (2) ◽  
pp. 147-164
Author(s):  
Radhakrishna G. Pillai ◽  
Ravindra Gettu ◽  
Manu Santhanam
Keyword(s):  
Drying Shrinkage ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Chloride Ingress ◽  
Shrinkage Cracking ◽  
Carbonation Resistance ◽  
Chloride Attack ◽  
Cementitious Systems

About a decade of research carried out at IIT Madras on cementitious systems has shown that the partial replacement of portland cement with supplementary cementitious materials (SCMs) has benefits as well as limitations. The SCMs do not adversely affect the long-term compressive strength and drying shrinkage of concretes, though there may be some compromise in workability and the resistance against plastic shrinkage cracking. Through the assessment of the chloride ingress rate in concrete and chloride threshold of steel, it is evident that the use of SCMs could significantly enhance the service life under chloride attack, though there is a reduction of the carbonation resistance. More importantly, SCMs can lead to significant reduction of the carbon footprint of concrete, and hence, are essential to achieve sustainability.

Finite Element Modeling of Drying Shrinkage in Concrete Blending with Mineral Admixtures

2011 ◽  
Vol 368-373 ◽  
pp. 1588-1594
Author(s):  
Tie Cheng Wang ◽  
Quan Min Peng
Keyword(s):  
Critical Factor ◽  
Drying Shrinkage ◽  
Moisture Diffusion ◽  
Shrinkage Strain ◽  
Mineral Admixtures ◽  
Granulated Blast Furnace Slag ◽  
Moisture Field ◽  
Adopted Model ◽  
Long Term Behavior

Drying shrinkage is a critical factor influencing the long-term behavior of concrete. In this paper, related parameters for calculating moisture field are discussed based on the theory of nonlinear moisture diffusion. Numerical simulation of shrinkage tests of concrete blending with fly ash and ground granulated blast furnace slag is conducted by ANSYS, considering the solution analogy between moisture field and temperature field. The calculated shrinkage strains are in good agreement with experimental results and the adopted model and finite elements method can be used to predict the time-dependent moisture field and shrinkage strain field in the real structure.

scholarly journals Polypropylene as a Retrofitting Material for Shear Walls

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2503
Author(s):  
Enea Mustafaraj ◽  
Yavuz Yardim ◽  
Marco Corradi ◽  
Antonio Borri
Keyword(s):  
Load Capacity ◽  
Shear Walls ◽  
Experimental Program ◽  
Test Results ◽  
Short Fibers ◽  
Epoxy Adhesives ◽  
Load Carrying ◽  
Energy Dissipation Capacity ◽  
Long Term Behavior

In recent years, on account of their excellent mechanical properties, composite materials (made of epoxy-bonded carbon, glass, or aramid fibers) have been used to reinforce masonry walls against in-plane actions. These materials have proven to be an effective solution for the strengthening of unreinforced masonry (URM) walls. Lately, research has shifted to the study of different types of fibers to avoid the use of epoxy adhesives, whose long-term behavior and compatibility with masonry are poor. This paper describes an experimental program that investigated the behavior of URM shear walls strengthened with two types of commercially available polypropylene products: short fibers (fiber length = 12 mm) and polypropylene nets. This investigation aimed to evaluate the influence of polypropylene reinforcement, embedded into an inorganic matrix, in terms of the improvement of the lateral load-carrying capacity, failure mechanism, ductility, and energy dissipation capacity of URM wall panels, where nine walls were subjected to in-plane loads using a racking test setup. The study showed that using two layers of polypropylene fibers embedded into a cementitious matrix greatly increased the in-plane load capacity of the brickwork masonry. On the other hand, the test results indicated that polypropylene nets, used as a repair method for cracked shear walls, cannot improve the structural performance of the walls.

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