Abstract: A joint sealing member such as may be used in civil engineering works for providing a watertight seal between joint members is disclosed. In one embodiment, the sealing member takes the form of a band-like member constituted by a central portion made of a water expansible material which expands upon absorbing water and lateral nonexpansible portions made of a rubber which does not change in volume when in contact with water. The thickness of the central portion is greater than that of the lateral portions. In another embodiment, the joint member takes the form of a belt-like base plate made of a water expansible material having one or more longitudinally extending rib-like ridge portions formed on one side thereof.

Abstract: The invention relates to a seal (1) for a joint comprising a cylindrical inner core layer (2) made of a water-unexpansible flexible material and having an internal opening (2a), and an outer coating layer (3) which is made of a water-expansible rubber. The outer coating layer (3) coats the inner core layer (2) and has penetrating openings (4) in the form of slits, pinholes or the like. The penetrating openings (4) extend to penetrating openings in the inner core layer (2) and communicate with the internal opening (2a) through the penetrating openings of the inner core layer (2).

Abstract: A seal, constituted by a water-expansible portion and a water-unexpansible portion, prevents water from leaking in a construction joint. The expansible portion surrounds the unexpansible portion everywhere except on a side of the unexpansible portion which is adhered to one of two mutually facing surfaces of the construction joint. The unexpansible portion is sized, relative to the overall size of the seal, particularly in the width dimension, so that it adheres with sufficient strength to one of the mutually facing surfaces of the construction joint so as not to become pulled off in use. An effective seal thus is maintained even in a swollen state.

Abstract: The waterstop used to prevent passage or leakage of water through a construction joint of concrete is shaped of a plastic or rubber in the form of a continuous-length belt-like form and provided with a water-swellable rubbery layer on at least a portion, or, for example, along the peripheries of the belt-like form, side-by-side coming into contact with the concrete bodies to serve as a water-tight filling of the joint by being swollen with water. The water-swellable rubbery layer is protected temporarily prior to use with a coating film of an alkali-soluble polymeric material which can at least partially be dissolved away by the alkalinity of the water in the concrete joint. The peripheries of the plastic- or rubber-made belt-like form are preferably in a length-wise bulged form having a bore running therethrough to serve as a stress absorber when the water-swellable rubbery layer is swollen with water.