Upgrading offshore pipelines concrete coated by silica fume additive against aggressive mechanical laying and environmental impact

• Inclusion of micro-silica to concrete actually leads to forms denser concrete.
• Impermeability may ensure better corrosion resistance and less risk to chemical attack.
• Micro-silica decreases the voids in concrete with increasing concentrations.
• Increasing both strength and flexure and reducing permeability which satisfies the aggressive environment and hard mechanical work.

Studies have been carried out to investigate the possibility of utilizing a broad range of micro-silica partial additions with cement in the production of concrete coating. This study investigated the strength properties and permeability of micro-silica concrete to achieve resistance toward concrete cracking and damage during laying. The chemical composition of micro-silica (silica fume) was determined, and has been conducted on concrete mixes with additions of 3 up to 25% by weight of cement in concrete. Properties of hardened concrete such as compressive strength, flexural strength, and permeability have been assessed and analyzed. Cubic specimens and beams were produced and cured in a curing tank for 7 and 28 days. Testing results have shown that additions of silica fume to cement between 5% and 7%, which acts as a filler and cementations material, developed high flexural and compressive strength with reduction of permeability.