The aggregates to use are granite aggregates and we need a compressive strength that is sufficient to carry commercial vehicles.
In general, to achieve a highly permeable concrete (pervious concrete) without compromising on the compressive and flexural strength. Use small size aggregate with around 5-7% sand, the CA/C ratio should be less than 4 and the w/c ratio of around 0.3. Use of comb polymer superplasticizer helped in achieving the desired permeability and strength.
Strength of such concrete can be increase by proper grading selection of CA in various sizes. Use of proper super plasticizer as well as certain fiber can increase the tensile strength of concrete which is appropriate of parking lot.
Dear Alex. At first thank you for your valuable question. And secondly, For sustaining a heavy vehicle load, the level of compaction of the subbase soil underneath the pervious layers (either of the porous concrete, or the gravel layer below) is the dominating factor. In addition, it would be much important to consider the flexural stregnth in such case than the compressive stregnth. A slab on elastic foundation will not be affected that much with the compressive stregnth rather than its flexural capacity. Thank you
Addition of steel fibres will definitely provide required flexural strength, tensile strength and toughness
Dear Dhirendra Singhal, I do agree with your good self that the addition of fibers will definitely provide the required flexural stregnth, but I'd prefer using non-steel fibers ( polypropylene or else ) in slabs where vehicles will be moving above. Thank you
Further info should be available below:
Article Pervious concrete as a sustainable pavement material – Resea...
http://www.vtt.fi/files/sites/class/D2_1_CLASS_WP2_SOTA_Permeable_Pavement_systems_and_materials.pdf
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