Effects of MgO-Based Expansive Agent on the Characteristics of Expansive Concrete

Expansive concrete are used to reduce cracking caused by drying shrinkage in concrete structures such as slabs, beams, columns, and pavement constructions. Although CaO and Sulphoaluminate based expansive agents have been used for decades, MgO-based expansive agents have demonstrated superior performance since 1970, especially for concrete dam structures. It has been proven that compensating shrinkage with MgO expansion efficiently prevents thermal cracking of mass concrete, reduces the expense of temperature control systems, and speeds up the construction process. This paper reviews several parameters such as reactivity, thickness of water film, curing condition, additive ratio, and calcination condition that affects expansibility, strength, soundness, durability, flowability, pore structures, crystal size, and hydration activity. The review indicates that the expansion characteristics of MgO may be designed flexibly by altering the calcination conditions (calcining temperature and residence time), maintaining a certain curing temperature, and tweaking its microstructure.

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.723.819 ◽

2016 ◽

Vol 723 ◽

pp. 819-823 ◽

Cited By ~ 1

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.

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Compressive Strength Gain Behavior and Prediction of Cement-Stabilized Macadam at Low Temperature Curing

Journal of Advanced Transportation ◽

10.1155/2020/2469436 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Yongli Xu ◽

Guang Yang ◽

Hongyuan Zhao

Keyword(s):

Compressive Strength ◽

Low Temperature ◽

Curing Temperature ◽

Strength Development ◽

Construction Process ◽

Strength Gain ◽

Estimation Model ◽

Maturity Method ◽

Temperature Ranges ◽

Natural Temperature

For cement-based materials, the curing temperature determines the strength gain rate and the value of compressive strength. In this paper, the 5% cement-stabilized macadam mixture is used. Three indoor controlled temperature curing and one outdoor natural curing scenarios are designed and implemented to study the strength development scenario law of compressive strength, and they are standard temperature curing (20°C), constant low temperature curing (10°C), day interaction temperature curing (varying from 6°C to 16°C), and one outdoor natural temperature curing (in which the air temperature ranges from 4°C to 20°C). Finally, based on the maturity method, the maturity-strength estimation model is obtained by using and analyzing the data collected from the indoor tests. The model is proved with high accuracy based on the validated results obtained from the data of outdoor tests. This research provides technical support for the construction of cement-stabilized macadam in regions with low temperature, which is beneficial in the construction process and quality control.

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Development of Simulation Program for Temperature Field of Mass Concrete Structures

E3S Web of Conferences ◽

10.1051/e3sconf/20183803020 ◽

2018 ◽

Vol 38 ◽

pp. 03020 ◽

Cited By ~ 1

Author(s):

Zheng Si ◽

Qian Zhang ◽

Ling Zhi Huang ◽

Dan Yang

Keyword(s):

Temperature Field ◽

Concrete Structure ◽

Relative Difference ◽

Maximum Temperature ◽

Mass Concrete ◽

Field Calculation ◽

Concrete Dam ◽

Roller Compacted Concrete ◽

Roller Compacted Concrete Dam ◽

The Difference

Most existing temperature field calculation programs have relative defects. In the present paper, based on merits of ANSYS platform, a temperature field calculation program of mass concrete structure is developed and demonstrated. According to actual pouring progress and thermodynamic parameters, a roller-compacted concrete dam is simulated. The difference of maximum temperature between calculated and measured values of measuring points is less than 1.8°C. Furthermore, the relative difference is -5%–5%. This result shows that the calculation program developed based on ANSYS platform can simulate and calculate the temperature field of mass concrete structure.

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Influence of Curing Temperature on the Deformation properties of Magnesium Oxide Micro-expansive Concrete

Proceedings of the 2016 International Conference on Civil, Transportation and Environment ◽

10.2991/iccte-16.2016.91 ◽

2016 ◽

Author(s):

Yun Dong ◽

Jianfeng Zhang ◽

Xia Chen ◽

Huaquan Yang

Keyword(s):

Magnesium Oxide ◽

Curing Temperature ◽

Expansive Concrete ◽

Deformation Properties

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Causes and Control Measures of Mass Concrete Crack of High-Rise Building Basement Foundation Slab

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.163-167.1609 ◽

2010 ◽

Vol 163-167 ◽

pp. 1609-1613 ◽

Cited By ~ 2

Author(s):

Hui Hong Feng ◽

Xi Wang

Keyword(s):

Control Measures ◽

Mass Concrete ◽

Construction Process ◽

Construction Stage ◽

Foundation Slab ◽

High Rise ◽

High Rise Building ◽

Concrete Crack ◽

And Control

This paper discusses that the causes and the corresponding control measures of mass concrete crack in the construction stage. And through the analysis of engineering example, it describes the application of the control measures of mass concrete crack in the basement foundation slab of high-rise building in construction process, and analyses the construction effect of its.

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Three-Dimensional Visual Simulation for Concrete Dam Construction Process

Communications in Computer and Information Science - Contemporary Research on E-business Technology and Strategy ◽

10.1007/978-3-642-34447-3_55 ◽

2012 ◽

pp. 612-619

Author(s):

Jiang Liu ◽

Chao Chang ◽

Ying Wei

Keyword(s):

Three Dimensional ◽

Visual Simulation ◽

Dam Construction ◽

Construction Process ◽

Concrete Dam

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Characterization tools for shrinkage-compensating repair materials

MATEC Web of Conferences ◽

10.1051/matecconf/201819907002 ◽

2018 ◽

Vol 199 ◽

pp. 07002

Author(s):

Benoît Bissonnette ◽

Samy-Joseph Essalik ◽

Charles Lamothe ◽

Marc Jolin ◽

Luc Courard ◽

...

Keyword(s):

Effective Strain ◽

Drying Shrinkage ◽

Portland Cement Concrete ◽

Cement Concrete ◽

Test Procedures ◽

Expansive Agent ◽

Change Behavior ◽

Repair Materials ◽

Field Quality ◽

Volume Change Behavior

Achievement of dimensional compatibility is one of the most important considerations in order to consistently achieve lasting repair works that do not undergo harmful cracking. Drying shrinkage of Portland cement concrete is generally inevitable and, although its magnitude can be reduced by optimizing or modifying the composition parameters, it remains significantly larger than its ultimate tensile strain. Conversely, the use of shrinkage-compensating concrete (ShCC) may allow to achieve a zero-dimensional balance with respect to drying shrinkage, through the use of a mineral expansive agent. The experimental work carried out in recent years at Laval University to evaluate the potential of shrinkage-compensating concretes (ShCC) for use as repair materials has in fact yielded quite promising results. Nevertheless, more research is required to turn ShCC systems into a truly dependable and versatile repair option. Among the issues still unresolved, suitable tests methods must be developed, not only to better characterize ShCC, but also to guide the specifications and perform field quality control. Efforts have thus been devoted to adapt or develop test procedures intended to better capture the particular volume change behavior of ShCC’s. The paper presents two test procedures intended to assess the shrinkage-compensating potential and the effective strain balance of ShCC in restrained conditions.

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Effect of Type of Cement and Expansive Agent on the Hardening of Steam-Cured Concrete

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.744.105 ◽

2017 ◽

Vol 744 ◽

pp. 105-113 ◽

Cited By ~ 1

Author(s):

Takayoshi Maruyama ◽

Hideaki Karasawa ◽

Shigeyuki Date

Keyword(s):

Early Stage ◽

Precast Concrete ◽

Curing Temperature ◽

Steam Curing ◽

Slag Powder ◽

Expansive Agent ◽

Cast Concrete ◽

Increase Productivity ◽

Early Strength ◽

Furnace Slag

Pre-cast concrete products are sometimes manufactured in two cycles daily. It is ensured that they have the required strength at an early stage of demolding by increasing the steam curing temperature to reduce cost or increase productivity. However, the reduction in durability because of cracking due to thermal stress is a topic of concern. On the other hand, it has been known that fine blast-furnace-slag powder and expansive agents show high temperature dependence. Although they are used even in precast concrete products, the effect of steam curing on these materials is not known. Thus, in this study, the expression of compressive strength and expansion that are critical in improving the quality and productivity of precast concrete products was investigated, using high early-strength cement and two types of expansive agents, namely, ettringite-based and lime-based agents. Consequently, the strength expression was accelerated by the addition of expansive agent to ordinary cement and high early-strength cement. The extent of restrained expansion is greater for the lime-based expansive agent than for the ettringite-based expansive agent, and when an expansive agent is added to high early-strength cement, the extent of restrained expansion falls to a level lower than that in the case of ordinary cement.

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Application of the High Early Strength Type Expansive Agent to the Blast Furnace Slag Combination Concrete with GGBFS under Steam Curing

MATEC Web of Conferences ◽

10.1051/matecconf/201927801005 ◽

2019 ◽

Vol 278 ◽

pp. 01005

Author(s):

Erica Enzaki ◽

Takashi Sakuma ◽

Eizou Takeshita ◽

Shigeyuki Date

Keyword(s):

Blast Furnace ◽

Blast Furnace Slag ◽

Early Stage ◽

Precast Concrete ◽

Curing Temperature ◽

Strength Development ◽

Steam Curing ◽

Expansive Agent ◽

Early Strength ◽

Furnace Slag

In recent years, the use of blast furnace slag material is being focused as environmental loading reduction and sustainable construction. However, in general, autogeneours shrinkage of the concrete using much amount of GGBFS is large in compared to normal concrete, therefore risk of cracking should be cared. On the other hand, strength development speed of concrete at early stage will be decreasing as the dosage of GGBFS increases, even under steam curing condition. It can be considered these points will be significant disadvantage in both productivity and quality of precast concrete. So in this study, early strength type expansive agent and setting accelerator were used in combination. As a result, it was confirmed that compressive strength at early stage is obviously increased. And steam curing temperature can be reduced about 10 degrees, and also, 600×10-6 of restraint expansion was obtained.

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