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Nishi ku, Japan

Higshiyama H.,Kinki University | Sappakittipakorn M.,King Mongkuts University of Technology Bangkok | Takahashi O.,Kanden LandA Company
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2015

From our previous findings, the recycling of ceramic waste aggregate (CWA) in mortar has been proved an ecological means plus an excellent outcome against chloride ingress. The CWAs were electric porcelain insulator wastes supplied from an electric power company, which were crushed and ground to fine aggregate sizes. In this study, to further develop the CWA mortar as an eco-efficient, ground granulated blast-furnace slag (GGBS) was incorporated. The GGBS was utilized as a supplementary cementitious material (SCM) at three different replacement levels of 15, 30, and 45% by weight of cement. The time dependency of the GGBS on enhancing chloride resistance in the CWA mortars was experimentally assessed by using an electron probe microanalysis (EPMA). The tests were carried out on mortar samples after immersion in 5.0% NaCl solution for 24, 48, and 96 weeks. Another set of the mortar samples was exposed to a laboratory ambient condition for 24, 48, and 96 weeks and then followed with a carbonation test. The resistance to the chloride ingress of the CWA mortar becomes more effective in proportion to the replacement level of the GGBS. Meanwhile, the carbonation depth of the CWA mortar increases with increasing the GGBS. The relationship between the apparent chloride diffusion coefficient and the GGBS replacement level was shown along with the immersion time. © 2014 The Society of Materials Science, Japan. Source


Higashiyama H.,Kinki University | Sappakittipakorn M.,King Mongkuts University of Technology Bangkok | Takahashi O.,Kanden LandA Company
Cement and Concrete Composites | Year: 2014

From our previous findings, the recycling of ceramic waste aggregate (CWA) in mortar has been proved an ecological means plus an excellent outcome against chloride ingress. The CWAs were porcelain insulator wastes supplied from an electric power company, which were crushed and ground to fine aggregate sizes. In this study, to further develop the CWA mortar as an eco-efficient construction material, ground granulated blast-furnace slag (GGBS) was incorporated. The slag (having the Blaine fineness of 6230 cm2/g) was utilized as a supplementary cementitious material (SCM) at three different replacement levels of 15%, 30%, and 45% of cement by weight. The efficiency of the GGBS on enhancing chloride resistance in the CWA mortars was experimentally assessed by using a silver nitrate solution spray method and an electron probe microanalysis (EPMA). The tests were carried out on mortar samples after immersed in a 5.0% NaCl solution for 24 weeks. Another set of the mortar samples was exposed to a laboratory ambient condition for 24 weeks and then followed with a carbonation test. The test results indicated that the resistance to the chloride ingress of the CWA mortar becomes more effective in proportion to the replacement level of the GGBS. In contrast, the carbonation depth of the CWA mortar increases with the increase of the GGBS. The activeness of the GGBS was also evaluated on the basis of the compressive strength development up to 91 days. Due to its high fineness, the GGBS can be used up to 30% while the high relative strength (more than 1.0) is achieved at all ages. © 2014 Elsevier Ltd. All rights reserved. Source


Higashiyama H.,Kinki University | Sappakittipakorn M.,King Mongkuts University of Technology Bangkok | Yamauchi K.,Kinki University | Takahashi O.,Kanden LandA Company
ISEC 2013 - 7th International Structural Engineering and Construction Conference: New Developments in Structural Engineering and Construction | Year: 2013

From a socio-economic sustainability point of view, a recycling of wastes as aggregates in cement-based materials has been noted a remarkable method. Ceramic wastes, which are discarded not only from ceramic industries but also electric power companies, are one of the materials possibly recyclable as aggregates. In this study, porcelain insulator wastes discarded from an electric power company are used as fine aggregate for mortar through the process of crushing and grinding. The aim of this study is to investigate the effectiveness of ceramic waste aggregate (CWA) in mortar on compressive strength and chloride ion penetration at different fine aggregates, at different quantity, and at various replacement ratios. From the experimental results, it was found that the CWA mortar was superior to either river sand or silica sand mortars. The compressive strength of the CWA mortar was higher than that of the river sand mortar and linearly increased with increasing the replacement ratio of the CWA. In addition, the chloride ion penetration depth linearly decreased with increasing the replacement ratio of the CWA. Copyright © 2013 by Research Publishing Services. Source


Higashiyama H.,Kinki University | Yamauchi K.,Kinki University | Sappakittipakorn M.,King Mongkuts University of Technology Bangkok | Sano M.,Kanden LandA Company | Takahashi O.,Kanden LandA Company
Construction and Building Materials | Year: 2013

In reinforced concrete structures, chloride ingress causes deleterious consequences due to corrosion of steel reinforcement. With no protective means, the service life of the structures is shortened proportionately to the rate of chloride ingress designated as a coefficient of chloride diffusion. Previous experimental study using the rapid chloride migration test has indicated that the use of ceramic waste aggregate (CWA) is effective in lowering the chloride diffusion coefficient of the 0.5 water to cement (W/C) ratio mortars and thus making mortars more durable. In this study, further experiments were conducted to seek visual evidences of the inhibiting of chloride ingress in the CWA mortars using a silver nitrate (AgNO3) solution spray method and an electron probe microanalysis (EPMA) after 24 weeks submersion in 5.0 wt.% sodium chloride solution. The CWAs tested at this time were electrical porcelain insulator wastes from an electric power company, which were crushed and ground in a recycle plant. In particular, the test program was extended to investigate the CWA mortars at a wider range of W/C ratios, i.e. 0.4, 0.5, and 0.6. All the CWA mortars were also compared with their counterpart mortars made of typical river sand (RS). It is visually found that, at the W/C ratio of 0.4, 0.5, and 0.6, the CWA mortar is more effective in resisting chloride ingress (having lower coefficient of apparent chloride diffusion) than the RS mortar. Moreover, the compression test was carried out. It is worth noting that the CWA has no adverse effect on the compressive strength of mortars in relation to river sand. © 2012 Elsevier Ltd. All rights reserved. Source


Higashiyama H.,Kinki University | Yagishita F.,Kinki University | Sano M.,Kinki University | Takahashi O.,Kanden LandA Company
Construction and Building Materials | Year: 2012

This paper presents the results of experimental investigation on compressive strength and resistance to chloride ion penetration of mortars made of ceramic waste as fine aggregate. The ceramic waste of electrical insulators provided from an electric power company in Japan has been crushed and ground to produce fine aggregates for mortars in this study. In the process of crushing and grounding, ceramic powder is discharged as a by-product. The effects of mixing with the ceramic powder in mortars have been also investigated. Compression tests of mortars are conducted at 7, 28 and 91 days curing. Moreover, the resistance to chloride ion penetration of mortars has been determined by two methods: the spraying of a 0.1 N silver nitrate solution and the X-ray fluorescence spectrometry. The compressive strength of mortar made of the ceramic waste aggregate increases and the resistance to chloride ion penetration is significantly higher in comparison with mortar made of the river sand. It is also confirmed that a partial replacement of cement by the ceramic powder up to 20% by weight is effective with respect to the compressive strength and the resistance to chloride ion penetration. © 2011 Elsevier Ltd. All rights reserved. Source

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