I need to know the provisions or parameters for casting concrete with fresh density above 2.4 gm per cc and hardened density above 2.35 gm per cc.
Cement- PPC, Coarse aggregate- mixture of 3/4 and 1/2 inch downgrade.
Wall thickness is 8 feet and slab thickness is 8.5 feet.
well, if you want to obtain high hardened density in concrete, you should use concrete ingredients having high density. For this aim, that is the easy way to use high density aggregates, for instance barite (BaSO4 ) aggregate, magnetite (Fe3O4) aggregate, limonite (2Fe2O3H2O) aggregate etc. they have 4.2 kg/dm3, 4.6 kg/dm3, 3.7 kg/dm3 densities respectively. through this way, you can obtain hardened concrete density above the 3.5. because aggregates is skeleton of the concrete, generaly changing the aggregate inclusion or aggregate type is preferred. ofcourse, you can use aggregates as fine, coarse or dust material. all ways bring you high density.
good luck
You can use mineral admixtures in the concrete which not only enhances its density but also improves strength properties and durability. Fine grained minerals such as Silica fume and water reducing admixture Superplasticiser could be a good option. Rather than changing the coarse aggregate types, concrete density mostly depends on the pores in it which depends on the coarse and fine aggregate size distribution and water to cement ratio. Adding finer grade silica fume can improve the density filling the pours and superplasticiser can reduce the water demand for workability which intern improves the density as well. One of the typical mix designs for you to have an idea is,
w/c ratio: 0.29, Cement: 486 Kg/m3, Fine Aggregate: 773 Kg/m3, Coarse Aggregate: 1044 Kg/m3, Water: 143 Kg/m3, Super plasticiser: 5.11 Kg/m3, and Silica fume: 25.55 Kg/m3.
This mix design is following the addition of 5% Silica fume and you could go up to 12% for optimum strength performance and durability. If you increase the silica fume proportions, increase the superplasticiser as well to balance the workability of the mix. In the mix design silica fume is supplied by ELKEM INDIA (Satisfies ASTMC-1240) and superplasticiser is CONPLAST SP 430 (Satisfies BIS 9103-1999).
Hope this helps.
The principal and more important subject to obtain a high density concrete is to use high density aggregates, because the aggregates have the 80 to 85% of the total volume of the concrete. Use dense aggregates from igneus or metamorphic origin is better in this case.
a concrete having a fresh specific mass of 2400 kg/m3 is a normal density mixture. For this reason no special ingredients are required to achieve the fixed goal. In particular, no high density aggregate are necessary.
if you have common aggregate - maximum size 32 mm - with ssa density of 2.7 kg/l the mixture proportion is as follows:
water 170 kg/m3
cement: 375 kg/m3
HRWR: 3,8 kg/m3
Aggregate (sand + coarse aggregates 32 mm max size): 1855 kg/m3
specific mass 2400 kg/m3
you can increase the specific mass adopting an aggregate with higher max size or you can increase the HRWR dosage in order to reduce the water demand and, consequently the amount of aggregates.
luigi coppola
I produced higher density concretes using steel slag aggregate. The density obtained depends on the percentage of the steel slag aggregate, The paper is published in ACI Materials Journal.
Use of Relatively High Fe2O3 Steel Slag as Coarse Aggregate in Concrete, ACI materials journal, Vol 109, No 4, 2012, pp 471-478
Good Morning.
If you want density about 2.35 you do not need to use special aggregates. Yo need to get a ratio w/c lowest possible,and an amount of cement about 350Kg. Obviously you need additives to reduce the amount of water.
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