Date: April 1, 2009
Testing Pervious Concrete? Well, for about three years a task group from ASTM has shared information with the goal of developing several test methods for Pervious Concrete. Due to the materials open gaped nature, we as technicians can’t use traditional concrete testing methods to assess quality in either its plastic or hardened states.
The task group, ASTM Subcommittee C09.49 on Pervious Concrete, has been reviewing a wide range of test methods developed all across the world. Members have been reviewing procedures for testing Pervious Concrete for compressive strength, flexural strength, in-place permeability, and in-place density.
To evaluate these proposed methods, members have been conducting round robin testing that seems to have universal applicability. When the task group members agree a certain procedure is valid, accurate, and repeatable, the procedure is presented for review by the ASTM International Committee C09 on Concrete and Concrete Aggregates.
The first of these proposed standards, ASTM C1688/C1688M, Test Method for Density and Void Content of Freshly Mixed Pervious Concrete, was approved by the C09 committee in late 2008.
The pervious committee has said that, we as producers can use the new standard to verify that the fresh Pervious Concrete delivered to a project corresponds to our mix proportions. This test method provides a procedure for determining the density and void content of freshly mixed Pervious Concrete. By measuring fresh density, the testing companies can verify mix proportions. The method is applicable to Pervious Concrete mixtures containing coarse aggregate with a nominal maximum size of 1 inch or smaller.
We may also discover that the approved test method has another benefit. It may also be used in developing other mix proportions. This may allow us as producers to develop a wider range of pervious mix designs incorporating various aggregate types, sizes, and gradations. We have to remember this test methods scope is very limited. It can not be used to determine the quality of the material after it is placed. Test results indicate that the fresh density and void content calculated from this test may differ from the in-place density and void content. This test should not be used to determine in-place yield.