The coarse aggregates are in two fractions 10 5 mm and 20 10 mm. Let these single sized coarse aggregates be combine in the ratio of 1:2 to get a graded coarse aggregate as per IS: 383-1970. The obtained grading of combined aggregates is given in Table 1. Concrete for Pumping Concrete Construction Magazine
For best pumpability, coarse aggregate grading should fall in the center of the gradation specifi ions. Porosity will affect pumpability if a significant amount of mix water is absorbed by the aggregate during pumping. When absorption causes problems, one solution is to thoroughly wet the aggregate stockpiles before batching the concrete.
The total content of fine aggregate in kg per cubic metre of concrete for various maximum size of coarse aggregate is shown in Table 20.50. Step by step design calculations for a pumpable concrete mix. Step 1: Draw the grading curve of aggregate Fig. 20.15 shows a more acceptable grading curve for pumpable concrete using 20 mm max. size aggregate.
If there is a deficiency in a locally available fine aggregate, concrete may benefit from the addition of air entrainment, additional cement, or a supplemental cementitious material SCM to address these shortcomings. Broad coarse-aggregate gradation ranges are listed in Table 2 of ASTM C 33.
For well-rounded aggregates this maximum size can be increased to 40 percent. Hence, a one and one-half inch gravel aggregate could be used in a pumping system with four inch openings. The properties of fine aggregate sand are more important in the design of pumpable concrete mixes than the properties of coarse aggregate.
Step 8 COARSE AGGREGATE CONTENT. 1895 – 815 = 1080 kg/m 3. The coarse aggregates are in two fractions 10 – 5 mm and 20 – 10 mm. Let these single sized coarse aggregates be combine in the ratio of 1:2 to get a graded coarse aggregate as per IS: 383-1970. The obtained grading of combined aggregates is given in Table 1.
Coarse-Aggregate Grading . The coarse aggregate grading requirements of ASTM C 33 permit a wide range in grading and a variety of grading sizes, as shown in Table 7-5; Mixture proportions should be, changed to produce workable concrete if wide variations occur in the coarse-aggregate grading; The maximum size of coarse aggregate used in ...
To produce dense and homogenous concrete this allows aggregates to pass through the reinforcement in congested areas. Grading Of Coarse Aggregates: Determination of particle size distribution for aggregate is grading and it affects the amount of water requirement, cement, workability, durability and pumps ability of concrete.