L-Arginine-Incorporated Cement Mortar as Sustainable Artificial Reefs

Abstract

L-arginine is one of the amino acids found in plant seeds. In the present study, various amounts (i.e., 3%, 5%, 10%) of L-arginine were added to cement mortar to investigate the compressive strength, workability, leaching behavior, and pH change in distilled and natural seawater, as well as dissolved nitrogen and growth of chlorophyll-a (Chl-a) by immersion in natural seawater. The compressive strength of the cement mortar is decreased with increase in L-arginine content owing to the high flow/slump and air content. A concentration of 10% L-arginine significantly promoted the growth of Chl-a on the cement mortar for up to 56 days of immersion in natural seawater. This is due to the availability of high dissolved nitrogen and pH inside the pores. This study recommends the use of L-arginine in artificial reef structures where marine ecosystems can be maintained.

Effect of Chloride Ions Concentrations to Breakdown the Passive Film on Rebar Surface Exposed to L-Arginine Containing Pore Solution

“…The amount of 0.115 M L-arginine (LA, purchased from Sigma-Aldrich, Seoul, Korea) was dissolved in the SP solution. The details about LA can be found elsewhere [27,33]. The passivation of steel rebars was performed by keeping them in SP + 0.115 M LA solution for 144 h. After that, different amounts of NaCl were added to determine the chloride threshold of the passive film.…”

Research on the Initial Settlement Depth of Artificial Reef on the Clay Seabed

“…The improvement of site selection standards. Many excellent results have been published in the field of artificial reef stability: Kageyama Y et al [3] studied the influence of different opening ratios and upflow angles on the stability of artificial reefs; Yun et al [4] proposed the use of ground nets and ground net bamboo mats to reduce The settlement and erosion of the ground; Hyun-Min Yang et al [5] improved the durability of artificial reefs by adding L-arginine to cement mortar. In terms of numerical simulation, Fujihara et al [6] applied numerical simulation to the field of artificial reefs for the first time, studying the distribution range and characteristics of upwelling in front of the artificial reef; Jinho Woo et al [7] studied the effects of different up-flow angles on the drag coefficient of the artificial reef influences; Li Xin et al [8][9] used data mining methods to study the stability of marine engineering construction and successfully applied them to GIL engineering Although many excellent methods have been proposed, few people consider the effect of the initial settlement on the stability of artificial reefs.…”