Influence of steel and polypropylene fibers on cracking due to heat of hydration in mass concrete structures

2018 ◽  
Vol 20 (2) ◽  
pp. 808-822 ◽  
Author(s):  
Muneer K. Saeed ◽  
Muhammad K. Rahman ◽  
Mohammed H. Baluch
2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Won-Chang Choi ◽  
Bae-Soo Khil ◽  
Young-Seok Chae ◽  
Qi-Bo Liang ◽  
Hyun-Do Yun

This paper presents experimental results that can be applied to select a possible phase change material (PCM), such as a latent heat material (LHM), to control the hydration heat in mass concrete structures. Five experimental tests (microconduction, simplified adiabatic temperature rise, heat, and compressive strength tests) were conducted to select the most desirable LHM out of seven types of inorganic PCM used in cement mortar and to determine the most suitable mix design. The results of these experimental tests were used to assess the feasibility of using PCM to reduce hydration heat in mass concrete that was examined. The experimental results show that cement mortar containing barium- [Ba(OH)2·8H2O] based PCM has the lowest amount of total hydration heat of the cement pastes. The barium-based PCM provides good latent heat properties that help to prevent volume change and microcracks caused by thermal stress in mass concrete.


2010 ◽  
Vol 163-167 ◽  
pp. 1776-1779
Author(s):  
Xiao Rong Shao ◽  
Liang Feng Zhu

Aimed to solve the problem that the mass concrete structures are apt to crack in underground engineering, this paper makes some research from the view of crack resistance performance of polypropylene fiber concretes. Since polypropylene fiber achieves waterproof through realizing of crack resistant, blending polypropylene fibers into concretes can reduce early contraction deformation of concretes, hinder emergence of plastic shrinkage cracking and improve impermeability of concretes, and its construction technology is simple. In practical application of this in anti-cracking and anti- seepage concrete structures in the International Terminal project of Hangzhou Xiaoshan International Airport, we find that mix of polypropylene fibers with concretes clearly improves anti-cracking and anti-seepage performance of concrete structures and meets design requirements of basements through measuring temperature and observing cracking condition of the mass concrete structures of basements on site. The project can provide experience for reference to similar projects.


MRS Advances ◽  
2018 ◽  
Vol 3 (34-35) ◽  
pp. 2051-2061
Author(s):  
Yunus Ballim

ABSTRACTThe hydration of cement is an exothermic reaction which generates around 300 kJ/kg of cement hydrated. In mass concrete structures such as dams and large foundations, this heat of hydration causes a significant rise in temperature in the internal sections of the concrete. If thermal gradients between the internal sections and the near-surface zone of the concrete element are sufficiently large, the thermal stress can cause cracking of the concrete. This cracking may cause functional or structural problems in the operation of the structure. In order to minimise the potential for such cracking, it is necessary to minimise the rate and amount of heat that is evolved, particularly during the early period of the hydration process. This can be achieved by design engineers and concrete technologists through judicious selection and processing of concrete-making materials. This paper presents the observations and results obtained over a number of years from adiabatic testing of concretes, computational modelling of temperature development in large concrete structures and direct temperature measurements in actual structures, with a view to understanding the effects of concrete-making materials on temperature development in concrete. The paper considers the effects of different types of rock aggregates, different types of Portland cement, fineness of grinding of the cement, the addition of supplementary cementitious materials and variations in the concrete starting temperature on temperature development in a large concrete element over time. The results indicate that using a coarser ground cement, adding significant amounts of supplementary cementitious materials and cooling the concrete mixture before placing has a more significant effect in reducing the risk of cracking than varying the aggregate type of the Portland cement type.


2013 ◽  
Vol 671-674 ◽  
pp. 2032-2037
Author(s):  
Chen Ming Yu ◽  
Jun Tong Qu ◽  
Zhi Hong Ran ◽  
Hao Ying ◽  
Fan Tao Meng

Distress in mass concrete is a problem in highway and bridge engineering. These mass concrete structures craze not by external loads, the temperature variation caused by heat of hydration and the temperature stress caused by concrete shrinkage are the main causes () for the leaks [1]. Therefore, the thermal stress and the temperature control have significant meaning in the mass concrete structures. Thermal cracks will break the structure globality and also decrease the durability of the structures during the construction time. In addition, the temperature variation will have a remarkable affection on the stresses variation of the structures during the service time [2]. This paper will discuss the temperature monitoring and the crack control projects of the mass concrete based on the cushion cap of an extradosed cable-stayed bridge which is being constructed.


This paper portrays an experimental research conducted to determine the strength and flexural behavior of the polypropylene fiber reinforced beams. Polypropylene fibers were being added in concrete with different dosages viz., 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6% to the total volume of concrete and Ordinary Portland Cement (OPC) and Portland Slag Cements (PSC) were added in the ratio of 60:40 with the overall cement content. Cubes were cast for compressive strength test and cylinder were cast for tensile strength test and beams were cast for flexural strength test. Seven beams were tested; one normal beam without polypropylene fiber and six beams with polypropylene fiber were cast and flexural strength test was conducted. Polypropylene fiber and slag cements were used in mass concrete structures to reduce heat of hydration and shrinkage cracks. Flexural strength and the cracking pattern were monitored during the test. The results indicated that the addition of polypropylene fibers and slag cements in concrete significantly increased the compressive strength, tensile strength, flexural strength and load carrying capacity of beams with different cracking patterns


2013 ◽  
Vol 405-408 ◽  
pp. 2739-2742 ◽  
Author(s):  
Zhen Hong Wang ◽  
Shu Ping Yu ◽  
Yi Liu

To solve the problem of cracks developing on thin-walled concrete structures during construction, the authors expound on the causes of cracks and the crack mechanism. The difference between external and internal temperatures, basic temperature difference and constraints are the main reasons of crack development on thin-walled concrete structures. Measures such as optimizing concrete mixing ratio, improving construction technology, and reducing temperature difference can prevent thin-walled concrete structures from cracking. Moreover, water-pipe cooling technology commonly used in mass concrete can be applied to thin-walled concrete structures to reduce temperature difference. This method is undoubtedly a breakthrough in anti-cracking technology for thin-walled concrete structures, particularly for thin-walled high-performance concrete structures. In addition, a three-dimensional finite element method is adopted to simulate the calculation of temperature control and anti-cracking effects f. Results show the apparent temperature controlling effect of water-pipe cooling for thin-walled concrete structures.


Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1847 ◽  
Author(s):  
Hoon Moon ◽  
Sivakumar Ramanathan ◽  
Prannoy Suraneni ◽  
Chang-Seon Shon ◽  
Chang-Joon Lee ◽  
...  

Blast furnace slag (SL) is an amorphous calcium aluminosilicate material that exhibits both pozzolanic and latent hydraulic activities. It has been successfully used to reduce the heat of hydration in mass concrete. However, SL currently available in the market generally experiences pre-treatment to increase its reactivity to be closer to that of portland cement. Therefore, using such pre-treated SL may not be applicable for reducing the heat of hydration in mass concrete. In this work, the adiabatic and semi-adiabatic temperature rise of concretes with 20% and 40% SL (mass replacement of cement) containing calcium sulfate were investigated. Isothermal calorimetry and thermal analysis (TGA) were used to study the hydration kinetics of cement paste at 23 and 50 °C. Results were compared with those with control cement and 20% replacements of silica fume, fly ash, and metakaolin. Results obtained from adiabatic calorimetry and isothermal calorimetry testing showed that the concrete with SL had somewhat higher maximum temperature rise and heat release compared to other materials, regardless of SL replacement levels. However, there was a delay in time to reach maximum temperature with increasing SL replacement level. At 50 °C, a significant acceleration was observed for SL, which is more likely related to the pozzolanic reaction than the hydraulic reaction. Semi-adiabatic calorimetry did not show a greater temperature rise for the SL compared to other materials; the differences in results between semi-adiabatic and adiabatic calorimetry are important and should be noted. Based on these results, it is concluded that the use of blast furnace slag should be carefully considered if used for mass concrete applications.


2021 ◽  
Vol 54 (6) ◽  
Author(s):  
Jianda Xin ◽  
Yi Liu ◽  
Guoxin Zhang ◽  
Zhenhong Wang ◽  
Ning Yang ◽  
...  

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