Curable water-swelling waterstop material, waterstop steel sheet pile, waterstop steel sheet pile production method, and water-stopping method

A curable water-swelling water stop material comprising:

• 100 parts by mass of a resin component which includes
• 40 to 100 parts by mass of a curable resin (A) having a hydrolysable alkoxysilyl group and
• 0 to 60 parts by mass of a polyether polyol(B);
• 0.3 to 25 parts by mass of an aminosilane coupling agent (C);
• 20 to 250 parts by mass of a water-absorbent resin (D);
• and
• 0 to 160 parts by mass of an extender pigment (E),
• wherein the hydrolysable alkoxysilyl group is represented by Formula (1)
• —X—CH2—SiR1Y(OR2)3-Y Formula (1)
• wherein X is a bonding functional group having a heteroatom with an unshared electron pair and bonding to a methylene group bonding to a silicon atom of a hydrolysable silicon group, R1 and R2 are C1-C3 alkyl groups respectively, and Y is 0, 1 or 2, and
• the aminosilane coupling agent (C) is 3-aminopropyltrimethoxysilane.