EVALUATION OF CONCRETING AGGREGATES RESISTANCE TO SILAGE EFFLUENT CORROSION

Five natural stone aggregates (basalt, limestone, gritstone and two ty pes of gravel) were tested for their resistance to corrosion by silage effluent. The aggregates were immersed in effluent for nine weeks and were periodically weighed to determine weight loss due to corrosion. Over the period of the experiment the average rates of weight loss for basalt, limestone, gritstone, gravel-1 and gravel-2 were respectively 2.3, 9.8, 0.7, 0.5 and 0.6% per week. Results presented show that cal cium content is a good predictor for rate of weight loss. It is conclu ded that, of the aggregates tested, gritstone would offer the most res istance to silage effluent attack. However the use of effluent resista nt aggregate needs to be further considered in view of the likely infl uence of corroded concrete on surface roughness.