EFFECT OF SEA WATER, COASTAL SAND, AND CLAM SHELL POWDER ON COMPRESSIVE STRENGTH OF NORMAL CONCRETE

Durability and resilience are essential factors of reinforced concrete structures in maritime environment which are subjected by stress, abrasion, and tidal exposure continuously. The research aims to analyze the effect of marine materials and its environment on the compressive strength of concrete cube (15x15x15 cm) at various days such as 7, 14, 28, and 56 days. The marine materials were used such as seawater, coastal sand, and clamshell powder as part of the concrete mixture. In addition, the effect of seawater on curing period, also were investigated. Treatment of marine environment were conducted by placing the samples after 28 days of age in tidal zone, submerged, and coastal atmospheric area.  The results show the marine environment decreased the compressive strength about of 2%, 11% and 19% for coastal atmosphere, tidal and submerged treatments respectively which correlated to carbonation depth. The use of coastal sand in concrete mixture decreased compressive strength of concrete while the presence of clamshell powder slightly increased compressive strength for both curing treatments in fresh water and seawater. The curing process in seawater until the 28-days had a similar of compressive strength rate with the ones in freshwater.