Properties of Roller Compacted Concrete with Pozzolan as Cement Replacement Material
Introduction:
Roller compacted concrete (RCC) gets its name from the heavy vibratory steel drum and rubber-tired rollers used to compact it into its final form. RCC has similar strength properties and consists of the same basic ingredients as conventional concrete_ well graded aggregates, cementitious materials, and water_ but different mixture proportions. The largest difference between RCC mixtures and conventional concrete mixtures is that RCC has a higher percentage of fine aggregates, which allows for tight packing and consolidation [1].
RCC may be considered for applications where no-slump concrete can be transported, placed, and compacted
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The same water was used for mixing and curing of concrete cubes.
Name of Test Results Coarse Aggregate Fine Aggregate
Specific gravity 2.56 2.63
Absorption (%) 0.51 0.71
Fineness Modulus 1.6 6.9
Table 3: Physical properties of aggregates
Pozzolan: The cement replacement material that used in the test was local natural pozzolan from Mont Popa. The chemical composition of pozzolan is given in Table 4. It is evident that the local natural pozzolan conforms to the requirements of ASM C 618 and hence, can be used as a partial replacement of the production of roller compacted concrete.
Description Composition (%) Local Natural Pozzolan Requirements as per ASTM for class N
Silicon dioxide (SiO2), aluminum oxide (Al2O3) and iron oxide (Fe2O3) 77.3 Min 70.00
Sulfur trioxide (SO3) 0.34 Max 4.00
Loss on ignition (%) 2.26 Max 10.00
Table 4: Comparison of local natural pozzolan with Class N of ASTM C 618
Method:
The soil compaction method is the most widely used mixture proportioning method for RCC pavements. This proportioning method involves establishing a relationship between the density and moisture content of an RCC mixture to obtain the maximum density by compacting samples over a range of moisture
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Firstly, 10-20 mm and 5-10 mm of aggregates were mixed in various proportions to find the combination with minimum voids content by Loose Bulk Density Test. According to the result shown in Fig 1, 64:36 ratios of 10-20 mm and 5-10mm were selected. And then, these two aggregate and 0-5mm aggregate were mixed with various ratio. Finally, minimum void were found in a combination of 38.4:21.6:40 ratios of 10-20 mm, 5-10 mm and 0-5 mm as shown in Figure