Abstract:
Studies have shown that there are problems of water capillary movement in buildings
erected in water logged areas and this always affects the lifespan of buidings. This research
work was therefore carried out to find solution to the problem using metal soap of long fatty
acids. Oil extracted from the seed of Huracrepitans using hexane in a soxhlet extractor,
analysed for fatty acid composition, and some physicochemical properties using standard
methods. Magnesium carboxylate was later produced from the oil using a two stage
synthesis. The first stage involves saponification of the oil to yield sodium
carboxylates(soap), the second stage involved metathesis, in which sodium was replaced
with magnesium, thus yielding the desired magnesium carboxylates. Concrete formulations
based on (0.2, 0.4, 0.6, 0.8 and 1% w/w) of magnesium carboxylates from Huracrepitans seed
oil were prepared, cast into identical and regular cuboids dimensions of (10.5 x 5.00 x
2.5mm). Blank casts were also made without magnesium carboxylate. All casted concrete
were allowed to cure for 28 days. They were subsequently oven-dried at 90oc for 24 hours.
Water absorptivity tests were later performed. The dominant fatty acid in the oil was oleic,
while the iodine value , saponification value, viscosity, specific gravity, and free fatty acid
were 170.432mg/I2/g, 242.0mg/kOH/g, 0.91g/m and 2.21 respectively. The performance of
water absorptivity tests showed that the magnesium carboxylate produced from
Huracrepitans seed oil reduced the capillary absorption. Concrete formulation based on 0.4%
magnesium carboxylate presented the least sorptivities. Application of magnesium
carboxylate at this concentration to concrete will therefore extend the service life of concrete
strenghths built in aggressive areas.
