Homogeneity and Strength of Mortar Joints in Pearl-Chain Bridges

The load carrying mortar joints in Pearl-Chain Bridges are cast vertically which means that they have a placing depth of up to 2.40 m. In the present paper, the feasibility of casting 2.40 m high homogeneous vertical mortar joints is examined. Three high-strength, expansive, self-compacting, ready-to-mix mortar products are tested.

To the authors’ knowledge, no previous published work has documented the homogeneity and properties of mortar joints of such a height. Hence, the present study documents a practical test procedure where the homogeneity of three mortar joints measuring 20 x 220 x 2400 mm has been tested and compared by measuring compressive strength, variation in rebound value, variation in density, and separation.

In addition, the appearance of the surface texture has been visually assessed. The measurements indicate that, for all three mortars tested, it is possible to cast homogeneous 2.40 m high mortar joints. Moreover, the strength of the three mortars meets the requirements for the Pearl-Chain Bridge application.

However, when inspected two of the mortars had many surface air bubbles which is a serious concern regarding durability of the mortar joints.