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Pro084-1

INFLUENCEOF MICROSCOPIC STRESS DAMAGE ON CARBONATION OF EXISTING BUILDING CONCRETE WITH FLY ASH



Author(s): XU Hongjing ,ZHAO Qingxin
Paper category: Proceedings
Book title: Proceedings of CONSEC13 Seventh International Conference on Concrete under Severe Conditions - Environment and Loading Volume I
Editor(s): Z.J. Li, W. Sun, C.W. Miao, K.Sakai, O.E. Gjørv, N.Banthia
ISBN: 978-2-35158-124-7
e-ISBN: 978-2-35158-134-6
Publisher: RILEM Publications SARL
Publication year: 2013
Pages: 895-901
Total Pages: 961
Language : English


Abstract: The effect of microscopic stress damage on carbonation of existing concrete structures is investigated in this paper. The fly ash replaced of cement in concrete with a water-binder ratio of 0.50 is 0, 20 %, 40 % and 60 %, respectively. After a scheduled period (28 days) of water curing, the samples were subsequently exposed in the climate room controlling temperature 20±1 °C and humidity 60±5 % until the testing date when the specimens had an the age of 3 months. According to GB/T50082-2009 (Chinese standard), the 7 days accelerated carbonation test was conducted in a test chamber kept at a temperature 20±2 °C, a relative humidity 70±5 %, and a CO2 concentration 20±3 % conditions for simulating the carbonation characteristics of existing building in service life. The microscopic stress damage in concrete specimens (100 mm×100 mm×400 mm) was precasted by universal testing machine, and the damage degrees defined by the ultrasonic wave velocity, were controlled at 0.18±0.02 by adjusting the loading level and cycles. Experimental results show that the microscopic stress damage can accelerate the carbonation of concretes. However, there is no way of knowing that the effect degree of microscopic stress damage on concrete carbonation. The stress damage impact factors of fly ash concrete, firstly decrease, and then increase as fly ash content increases. In addition, the smallest stress damage impact factor is 0.528 when the fly ash replacement ratio is 40 %, which indirectly implies that the structure with appropriate fly ash replacement ratio has perfectly self-repairing ability.


Online publication : 2013
Publication type : full_text
Public price (Euros) : 0.00


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