Influence of slag on leaching behavior of cement mortar lined in ductile iron pipe under a flowing solution. (15th January 2017)

• Record Type: Journal Article
• Authors: Tang, Yu-Juan; Zuo, Xiao-Bao; Yin, Guang-Ji; He, Shao-Li; Ayinde, Olawale
• Is Part Of: Materials & design. Volume 114(2017)
• Page Start: 612
• Page End: 622
• Publication Date: 2017-01-15
• Subjects: Slag -- Cement-mortar lining -- Calcium leaching -- Ductile iron pipe -- Flowing solution; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2016.11.096
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: In order to investigate the influence of slag on the leaching behavior of cement mortar lined in ductile iron pipe in a flowing solution, two types of ductile iron pipe specimens lined with ordinary- and 40% slag- cement mortar are firstly prepared, then, an accelerated leaching experiment on the prepared specimens is carried out by using a 6 M ammonium chloride solution at a flow rate of 0.3 m/s. The parameters of linings at different leaching times, such as porosity, pore size distribution, phase composition and Calcium-Silicon (Ca/Si) ratio, were analyzed by using the saturation-drying weighing method, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy in back scattered electron mode (ESEM-BSE) measurements. Results show that, the mixture of 40% slag in cement-mortar lining can reduce its initial porosity and Calcium-Silicon ratio, and improve its pore size distribution and phase composition. In the accelerated leaching process, the porosity, phase composition and Calcium-Silicon ratio of the slag-cement-mortar lining with 40% slag have smaller change than that of the ordinary-cement-mortar lining without slag, and it indicates that the addition of slag can effectively improve the calcium leaching resistance of cement-mortar lining in ductile iron pipes in water supply engineering. Graphical abstract: Highlights: A new experimental method of accelerated leaching is developed for the corrosion evaluation of cement-mortar lining under a flowing solution. The accelerating factor of 6M NH4 Cl solution is 40, so the relation of accelerated and conventional leaching of lining is obtained. The addition of 40% slag to lining can improve its microstructure, slow down its leaching process, and enhance its leaching resistance.