Only material conforming to specifications for normal-weight aggregate (ASTM C33) or lightweight aggregate for structural concrete (ASTM C330) is accepted under the ACI 318 Building Code without special tests. When an aggregate for which no experience record is available is considered for use, the modulus of elasticity and shrinkage as well as the compressive strength should be determined from trial batches of concrete made with the aggregate. In some localities, aggregates acceptable under C33 or C330 may impart abnormally low ratios of modulus of elasticity of strength (Ec /Æ’’c) or high shrinkage to concrete. Such aggregates should c c not be used.
