Sensitivity of solidification hydration model in estimating carbonation of fly ash cement system

2021 ◽  
Vol 282 ◽  
pp. 122582
Author(s):  
Yuguo Yu ◽  
Tianyu Zhang ◽  
Qihan Wang ◽  
Xiaojun Chen ◽  
Di Wu ◽  
...  
2012 ◽  
Vol 446-449 ◽  
pp. 2708-2713 ◽  
Author(s):  
Qin Li ◽  
Xiao Jun Zhou ◽  
Zhuo Yin Jiang ◽  
Ke Wei Sun

An comparison research on the effect of pozzolanic reactions of fly ashes in architectural wastes recycle is described in the paper. In the experiment, NaOH and Na2SO4-Ca(OH)2 were used to activate the pozzolanic activities in the fly ashes—cement system to solidify the architectural wastes. The macro and micro testing methods were used to test the compressive strength, phase and electronic micro morphology of the hydration of alkali-activated fly ashes—cement cementitious system. The testing result shows that proper alkali-activated fly ashes—cement cementitious architectural wastes can shorten the incubation time of the pozzolanic reactions of fly ashes, whi ch make the reactions of fly ashes more sufficient. So the hydration products of fly ashes —cement cementitious system with alkali additions were more than those of without alkali add itions, and the compressive strength of the alkali-activated fly ashes—cement cementitious system is higher than that of non alkali-activated fly ashes—cement cementitious system.


2010 ◽  
Vol 168-170 ◽  
pp. 532-536 ◽  
Author(s):  
Guo Li ◽  
En Li Lu ◽  
Peng Wang ◽  
Ou Geng ◽  
Yong Sheng Ji

In order to study the influences of initial curing conditions on fly ash (FA) cement concrete durability, fly ash cement samples with 30% replacement ratio were fabricated and cured in water at 10°C, 20°C, 30°Cand 40°C for 3d, 7d, 14d and 28d respectively. Hydration degrees of fly ash at early age were measured using the selective dissolve method. Correspondingly the pore structure and morphology of FA-cement mortar and compared cement mortar were studied by using MIP and SEM methods. Then early age compressive strengths of FA-cement concrete and compared normal cement concrete were tested. Experimental results show that initial curing temperatures and ages are important factors to fly ash early age hydration degree, FA-cement system microstructure, morphology and early age compressive strength etc. High curing temperatures and longer curing time can lead higher fly ash hydration degree, and then higher compressive strength of FA-cement concrete, and make the micro-structures of fly ash-cement system denser.


2021 ◽  
Vol 9 (7) ◽  
pp. 2804-2815
Author(s):  
Jionghuang He ◽  
Guangcheng Long ◽  
Kunlin Ma ◽  
Youjun Xie ◽  
Zhiqing Cheng
Keyword(s):  
Fly Ash ◽  

2009 ◽  
Vol 1 (1) ◽  
pp. 1-4
Author(s):  
Mohamed J. S. Z. ◽  
Mohamed S.N.

Concrete deterioration is one of the most concern matters in construction world. The concrete deterioration such as efflorescence should not be ignored. The efflorescence is a deposit salts, usually white, formed on a surface of concrete. The efflorescence is not a major problem that leads to structural defects but it can build unattractiveness to the structure such as brick wall and concrete mortar. The way to prevent the efflorescence occurrence is by studying the results of testing such as absorption and efflorescence itself to reduce the efflorescence. The non-modified cement system can reduce the efflorescence but cannot avoid it because of the reaction of cement hydration itself. This study is to prove that by using a modified cement system such as Pulverized Fly Ash (PFA) and Polymers (water based latex grade 29Y46), the efflorescence of the mortar can be prevented. The results from this study proved the modified mortar which is a sample with PFA and Polymers has higher strength, durability, and less efflorescence compared with the non-modified cement system.


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