Foundation, Concrete and Earthquake Engineering

Requirements for Wash Water for Using in Ready-Mixed Concrete

In permitting water to be used in mixing of concretethe quality should be potable and many other chemical and biological aspects also should consider . Now question is wash out water can be used in further concreting operation.

The wash water received from washout operations of mixer can be used if it complies with limit stated in table-1 provided below. This table provides limits for physical test of questionable water.

Table-1: the criteria for accepting wash water supply
Criteria for accepting wash water supply for Using in ready mixed concrete
Regarding application of air-entrainment and chemical admixtures of other forms ASTM C94/C94M-00 provides that special attention should pay to determine the rate of dosages and sequence of batching. These determined amount and sequences should apply to consecutive batches.

ASTM C94/C94M specifies the requirement for ready mixed concrete. We will publish numerous post regarding requirements and specifications for ready mixed concrete. For convenience of reader we will sometimes provide combination of ASTM and ACI specifications for particular topics regarding ready mixed concrete.
Regarding testing frequency ASTM specifies that throughout the first 4 weeks the test should be conducted in a interval of a week. After that a monthly interval of testing can be accepted frequency. In each test the results must not exceed the limit stated in table-1.

The purchaser can specify the testing frequencies for chemical limits or the frequencies specified before can be used for these tests.

The chemical limit test is specified as option in this standard. But purchaser can specify to test for these limits. 

Table-2: optional limits for chemical content in wash water
Optional limits for chemical content in wash water in ready mixed concrete

No comments:

Post a Comment