Author: Haroon Khalil

Preventive measures for cracks in concrete are discussed in Section 8.11. Apart from them, joints in concrete structures are provided to continue a specific work or prevent cracks due to change in temperature. The following two types of joints are usually provided in concrete structures: 1. Construction Joints This type of joints are provided at…

Cracks in concrete may be plastic shrinkage cracks, settlement cracks, cracks due to bleeding, cracks due to delayed concrete casting and cracks due to construction effects.

Causes of cracks, remedial measures and repair of cracks in concrete are discussed.

In order to keep the stone masonry free from damp, efflorescence, frost action, etc., colourless waterproofing materials is applied waterproofing materials obtained from heavy petroleum distillates, oils or in soluble soaps are best. It is difficult to waterproof very closely textured stones. Waterproofing materials substances containing resins are not suitable for fine-textured stonework. Waterproofing causes…

Repairing of cracks has to be attended by ensuring that the settlement causing the crack has ceased. This generally takes about one year for the complete settlement. Small cracks are cleaned with a wire brush and a thick paste of cement mix is forced into the crack. In order to get a firm key for…

Removal of stains can be done easily if its origin is known. Iron stains show rusty appearance which can be removed by rinsing the area with a solution of ½ kg oxalic acid in 5 l of water. After 2–3 hours, the surface should then be scrubbed with brush and clean water. Darker stains may be removed…

Appearance of efflorescence occurs commonly due to use of certain type of mortars. Removal of efflorescence has to be done as done in brickwork. Stones are to be kept saturated with water to remove the action of acids.

Maintenance of stonework involves in removing efflorescence and stains, repair of cracks and waterproofing.

Re-painting is necessary for walls which have been previously painted. The type of paint and colour should be decided and accordingly the surface has to be prepared.

In the case of brickwork which are pointed may be needed to re-point in order to improve the appearance and to make it water tight. Generally mortar at the pointed portions gets lost due to rain, wind, freezing, etc. Following procedure may be followed for re-pointing: