On Workability and Pumpability of Superplasticized Concrete with Large Size Aggregate
H. Yoshida, H. Kasami, S. Suzuki,
T. Takahashi, and Y. Yoshioka
Appears on pages(s):
aggregate size; air-entrained concretes; air entrain-ment;
coarse aggregates; compressive strength; concrete durability;
naphthalene compounds; plasticizers; pumped concrete; slump tests;
This paper presents the results of a series of laboratory and field studies conducted to determine the engineering properties of superplasticized concrete made of large size aggregate. To find out the effects of dosage of superplasticizer on workability, laboratory studies were conducted on air-entrained concrete mixes having 40mm and 60mm maximum sized aggregates. The fluidizing effect of superplasticizer on such concrete was found to be similar as those in concrete with smaller aggregate, and workability increased with the dosage up to a certain content without significant reduction in entrained air and strength. Field studies were also conducted on the pumpability of superplasticized concrete of large size aggregate. Six mixes of concrete with and without superplasticizer were pumped horizontally through an 8 in. pipeline, 92m in length, and were tested for slump, air content and compressive strength before and after pumping. Pumping pressure, line-pressure and line-pressure-loss were measured at various pumping rates. The test results indicated that superplasticized concrete with large size aggregate can be pumped under 10 to 20 percent lower pumping pressure and line pressure than those of control concrete without deterioration in the properties of fresh and hardened concrete.