Use of ferrocement as secondary gate of fishponds.

Abstract

Ferrocement was first used in the Department in fabrication of broodstock and hatchery tanks for shrimp. In 1981, the Capital Outlay Project at Leganes called for the design and construction of 210 gates, consisting of 2 main gates, 111 secondary gates and 96 tertiary gates. Of the secondary gates, 97 were designed using ferrocement, with 30 and 67 of the sluice culvert type, respectively.

Ferrocement gates were fabricated in panels at a central work station and assembled at site. Panel geometry was controlled such that it could be carried by two or three laborers. A standard mixture ratio of 1:2 (cement:sand) with minimum amount of water was used. Several reinforcing bars arrangement were used with a single layer of gauge No. 20 welded 12 mm × 12 mm wire mesh or chicken wire.

Construction cost appears favorable with respect to reinforced concrete gates but costs more than an equivalent wooden gates. After 3–4 years the ferrocement gates appear to be still functional. The potential is great with more improvements to be undertaken.