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Acid-resistant material “RECOSUL” utilizing sulfurAn application for new construction and/ormending of spa facilities
Yoshitaka OOTA
Sulfur-utilizing group, Research and development dept., Nippon Oil Corporation

Abstract
Though cement-concrete (concrete, hereafter) is an economical construction material
having long-term durability, erosion problems are recently occurring in concrete materials used in sewerage, acid rivers and spa facilities. To provide for these erosion measures,
coating method and seat-lining method have been implemented so that concrete is out oftouch with acid materials. On another front, acid-resistant concrete has also beendeveloped.
As an excellent substitute for concrete used in acidic condition, we have developed
the modiﬁed sulfur-based acid-resistant material “RECOSUL” (RRecycled and EcologicalEcomaterial using sulfur).
sulThe characteristics of RECOSUL and its application for new
construction and/or mending spa facilities are mentioned in this article.
Key words : Modiﬁed sulfur, Solidify, Aggregate, Binder, Acid-resistant, Compressive
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Production method of RECOSUL

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  (RECOSUL)  *+ (R234 . 5676891 :;<.= >?@ $ABCD E&FGHIJ" K+) LAMN !"

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Z \'  @ Lg A+4DF$ !"#\[K'  X"

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136
Table +

Basic characteristics of acid-resistant RECOSUL
RECOSUL

Concrete(,2days age)

Modiﬁed sulfur (,+)
Silica sand (03)Fly ash (+*)

Water-cement
ratio : .0ῌ

,4-,4-

. (air volume)

Compressive (N/mm ) strength/.43-/JIS A ++*2 (f/* mm)Flexural (N/mm ) strength+*4+0

JIS A ++*0 (+**%+**%.** mm)Tensile strength (N/mm ).4-2

Composition (wtῌ)

Density (g/cm-)
Void (volῌ),,,+Expansion factor (K )JIS A +++- (f+** mm)

0Remarks

0+24*%+*+*,*%+*

Water coe$cient absorption(wtῌ)

*4+3

Water (cm,/sec) permeability*4**%+*/+4--%+*/JIS A +-,/ (+*0*)Permeability test for concrete
Imput method (*4/ MPa)

Table , Weight transition of RECOSUL specimens during dipping in acid solution Dipped in / wtῌsulfuric acid(for -*days)Dipped in +* wtῌ sulfuric acid(for 0*days)
Weight (g)BeforedippingAfterdipping

Weighttransitiong (wtῌ)No4 ++/*+42+/*/4,-4. *4,-

No4 ,+..34,+./,4*,42 *4+3

SpecimenNo4

Weight (g)BeforedippingAfterdipping

Weighttransitiong (wtῌ)No4 ++./+42+./343

24+ *4/0ῌ

No4 ,+..142+.//4/141 *4/-ῌ

Specimen
No4Transition ratio (wtῌ)*4,, : /ῌ  +*ῌ :Transition ratio (wtῌ)*4//ῌ +./   !" #$ !" 1./ cmf%+/ cmH , &'( )* : / ῌ -* + +*ῌ  0* +
ῌ !,-.
/ῌ  -* + -. /01234567' 8 !"9:23;<=>?@A B ,C D !"EFGH IJKJLM3NO!PQR
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Fig. , Compressive strength transition during dipping in +* wtῌ hydrochloric acidsolution (JSTM C 1.*+)

Fig. -137

Dipped specimens after 0 months   !" #$
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138

Fig. . An example of construction at Shingashi water reclamation center of Tokyo breau of sewage(Replacement of the sewage return box)

Fig. /   Examples of practice in spa facilities !"#

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