4130.01 REVETMENT DESCRIPTION.

A. Broken limestone, dolomite, quartzite, or granite from an approved source as described in Materials I.M. 409.

• A minimum of 50% of the stone or broken concrete revetment shall be composed of beds or slabs more than 5 inches (125 mm) thick.
• A minimum of 10% of the beds or slabs shall be thick enough to produce the required weight (mass) of either the stone or concrete with the greatest dimension not more than two times the smallest dimension.

B. When the source test plot or service history is not available, meet the following requirements for virgin stone crushed to 3/4 inch to 1 1/2 inch (19 mm to 37.5 mm) nominal maximum sizes:

REVETMENT TYPE	REVETMENT QUALITY	TEST LIMITS	TEST METHOD
Primary projects; Class A & B revetment	Alumina	0.7	Iowa 222
All projects; Class E revetment	A Freeze	10	Iowa 211, Method A
	Secondary Pore Index	25	Iowa 219
Non-Primary projects; Class A & B revetment	C Freeze	5	Iowa 211, Method C
All projects; Class D revetment	C Freeze	10	Iowa 211, Method C
Erosion Stone	C Freeze	15	Iowa 211, Method C
Note: Revetment may pass either Alumina or A-Freeze for compliance.

Abrasion loss for all revetment and erosion stone not to exceed 50% when tested according to AASHTO T 96.

C. Recycled PCC revetment or broken concrete meeting the requirements of Materials I.M. 210 may be used as revetment with the approval of the Engineer.

• Trim steel so that protrusions are less than 1.2 inch (12 mm) All reinforcement material shall be cut flush with the flat surface of the concrete.
• A minimum of 50% of the stone or broken concrete revetment shall be composed of beds or slabs more than 5 inches (125 mm) thick.
• A minimum of 10% of the beds or slabs shall be thick enough to produce the required weight (mass) of either the stone or concrete with the greatest dimension not more than 2 times the smallest dimension.
• No petroleum based or HMA material shall be included in revetment material.

4130.02 REVETMENT GRADATION.
Gradation compliance is determined by visual inspection, monitored by the Engineer. The Engineer may designate material as too fine or too coarse.

A. Class A Revetment.

• Nominal top size of 400 pounds (180 kg).
• At least 75% of the stones shall weigh more than 75 pounds (35 kg).
• None less than 50 pounds (25 kg).
• Stones shall have at least one flat face with one dimension at least 15 inches (375 mm).

B. Class B Revetment.

• Nominal top size of 650 pounds (300 kg).
• At least 20% of the stones shall weigh more than 500 pounds (225 kg).
• At least 50% of the stones shall weigh more than 275 pounds (125 kg).
• At least 90% of the stones shall weigh more than 25 pounds (10 kg).

C. Class D and Class E Revetment.

• Nominal top size of 250 pounds (115 kg).
• At least 50% of the stones shall weigh more than 90 pounds (40 kg).
• At least 90% of the stones shall weigh more than 5 pounds (2 kg).
• The Engineer may approve using riprap containing material larger than 250 pounds (115 kg).

Additional processing is not required for Class D material. After visual inspection and prior to loading, the Engineer may designate material as too fine or too coarse. Mechanically process Class E material to remove material 3 inches (75 mm) and less.

4130.03 EROSION STONE DESCRIPTION.
Broken limestone, dolomite, quartzite, granite, or broken concrete with steel removed.

4130.04 EROSION STONE GRADATION.
Gradation compliance is determined by visual inspection, monitored by the Engineer. The Engineer may designate material as too fine or too coarse.

• Nominal 6 inch (150 mm) size.
• 100% passing the 9 inch (225 mm) screen.
• 100% retained on the 3 inch (75 mm) screen.

4130.05 EROSION STONE QUALITY.

TABLE 4130.05
Aggregate Quality	Maximum Percent Allowed	Test Method
C Freeze	15	Iowa DOT Materials Laboratory Test Method 211, Method C
Abrasion	50	AASHTO T 96
Clay Lumps and Friable Particles	5	Materials I.M. 368
Note: Tests are performed on product crushed to 3/4 inch (19 mm) or 1 inch (25 mm) top size.

There are no quality requirements for recycled concrete.