Changes

The installation of pervious concrete requires the placement of ready-mix into forms. Unlike permeable pavers, pervious concrete also requires extensive curing time. Pervious concrete has the most particular installation requirements of the various permeable pavement types. It is recommended that contractors with certifications for the installation of pervious concrete, such as NRMCA certifications, are tasked with its installation.

The installation of pervious concrete requires the placement of ready-mix into forms. Unlike permeable pavers, pervious concrete also requires extensive curing time. Pervious concrete has the most particular installation requirements of the various permeable pavement types. It is recommended that contractors with certifications for the installation of pervious concrete, such as NRMCA certifications, are tasked with its installation.

Construction Steps:

'''Construction Steps:'''

#Install 10 mm vertical spacers on the forms.

#Install 10 mm vertical spacers on the forms.

#Dampen the sub-base prior to the placement of pervious concrete with a pressure mister. Doing so helps to avoid interfering with the dry mix’s critical moisture content.

#Dampen the sub-base prior to the placement of pervious concrete with a pressure mister. Doing so helps to avoid interfering with the dry mix’s critical moisture content.

Note: Throughout the process of pouring concrete, the moisture content of the ready mix should be periodically adjusted to meet specification.

Note: Throughout the process of pouring concrete, the moisture content of the ready mix should be periodically adjusted to meet specification.

Key Inspection Points:

'''Key Inspection Points:'''

*Climate conditions are acceptable for placement. Ideal conditions include the following:

*Climate conditions are acceptable for placement. Ideal conditions include the following:

**Temperature of about 15°C

**Temperature of about 15°C

*Wash-out areas are provided for concrete trucks and other equipment.

*Wash-out areas are provided for concrete trucks and other equipment.

Mistakes to Avoid:

'''Mistakes to Avoid:'''

*Delivery of excessively wet ready-mix - It is easier to receive ready mix that is on the dry side and add moisture than it is to dry it out. Excess moisture can result in glazing and placing excessively dry concrete can result in raveling.

*Delivery of excessively wet ready-mix - It is easier to receive ready mix that is on the dry side and add moisture than it is to dry it out. Excess moisture can result in glazing and placing excessively dry concrete can result in raveling.

*Adding moisture with a hose – do not use the hose from the ready-mix truck to add moisture to the subbase or concrete surface. This will separate the rock and cement base of the concrete, resulting in excessive raveling. Only a pressure mister should be used.

*Adding moisture with a hose – do not use the hose from the ready-mix truck to add moisture to the subbase or concrete surface. This will separate the rock and cement base of the concrete, resulting in excessive raveling. Only a pressure mister should be used.