Technical Report Documentation Page

+---------------------+---+------------+---+---------+-------+----------+
| 1\. Report No.      |   | 2\.        |   |         | Re    |          |
|                     |   | Government |   |         | cipie |          |
|                     |   | Accession  |   |         | nt\'s |          |
|                     |   | No.        |   |         | Ca    |          |
|                     |   |            |   |         | talog |          |
|                     |   |            |   |         | No.   |          |
+---------------------+---+------------+---+---------+-------+----------+
| 4\. Title and       |   |            |   | 5\.     |       |          |
| Subtitle            |   |            |   | Report  |       |          |
|                     |   |            |   | Date    |       |          |
| Concrete Pavement   |   |            |   | June    |       |          |
| Rehabilitation --   |   |            |   | 2001    |       |          |
|                     |   |            |   |         |       |          |
| Guide for Diamond   |   |            |   |         |       |          |
| Grinding            |   |            |   |         |       |          |
+---------------------+---+------------+---+---------+-------+----------+
|                     |   |            |   | 6\.     |       |          |
|                     |   |            |   | Per     |       |          |
|                     |   |            |   | forming |       |          |
|                     |   |            |   | Organ   |       |          |
|                     |   |            |   | ization |       |          |
|                     |   |            |   | Code    |       |          |
+---------------------+---+------------+---+---------+-------+----------+
| 7\. Author(s)       |   |            |   | 8\.     |       |          |
|                     |   |            |   | Per     |       |          |
| Angel L. Correa,    |   |            |   | forming |       |          |
| (404)562-3907,      |   |            |   | Organ   |       |          |
| Angel.              |   |            |   | ization |       |          |
| Correa@fhwa.dot.gov |   |            |   | Report  |       |          |
|                     |   |            |   | No.     |       |          |
| Bing Wong,          |   |            |   |         |       |          |
| (202)366-2169,      |   |            |   |         |       |          |
| Bin                 |   |            |   |         |       |          |
| g.Wong@fhwa.dot.gov |   |            |   |         |       |          |
+---------------------+---+------------+---+---------+-------+----------+
| 9\. Performing      |   |            |   | 10\.    |       |          |
| Organization Name   |   |            |   | Work    |       |          |
| and Address         |   |            |   | Unit    |       |          |
|                     |   |            |   | No.     |       |          |
| Federal Highway     |   |            |   | (TRAIS) |       |          |
| Administration      |   |            |   |         |       |          |
|                     |   |            |   |         |       |          |
| Southern Resource   |   |            |   |         |       |          |
| Center              |   |            |   |         |       |          |
|                     |   |            |   |         |       |          |
| 61 Forsyth St, SW,  |   |            |   |         |       |          |
| Suite 17T26         |   |            |   |         |       |          |
|                     |   |            |   |         |       |          |
| Atlanta, GA 30303   |   |            |   |         |       |          |
+---------------------+---+------------+---+---------+-------+----------+
|                     |   |            |   | 11\.    |       |          |
|                     |   |            |   | C       |       |          |
|                     |   |            |   | ontract |       |          |
|                     |   |            |   | or      |       |          |
|                     |   |            |   | Grant   |       |          |
|                     |   |            |   | No.     |       |          |
+---------------------+---+------------+---+---------+-------+----------+
| 12\. Sponsoring     |   |            |   | 13\.    |       |          |
| Agency Name and     |   |            |   | Type of |       |          |
| Address             |   |            |   | Report  |       |          |
|                     |   |            |   | and     |       |          |
| Federal Highway     |   |            |   | Period  |       |          |
| Administration      |   |            |   | Covered |       |          |
|                     |   |            |   |         |       |          |
| 400 7^th^ Street    |   |            |   |         |       |          |
| S.W.                |   |            |   |         |       |          |
|                     |   |            |   |         |       |          |
| Washington, DC      |   |            |   |         |       |          |
| 20590               |   |            |   |         |       |          |
+---------------------+---+------------+---+---------+-------+----------+
|                     |   |            |   | 14\.    |       |          |
|                     |   |            |   | Spo     |       |          |
|                     |   |            |   | nsoring |       |          |
|                     |   |            |   | Agency  |       |          |
|                     |   |            |   | Code    |       |          |
+---------------------+---+------------+---+---------+-------+----------+
| 15\. Supplementary  |   |            |   |         |       |          |
| Notes               |   |            |   |         |       |          |
+---------------------+---+------------+---+---------+-------+----------+
| 16\. Abstract       |   |            |   |         |       |          |
|                     |   |            |   |         |       |          |
| This Technical      |   |            |   |         |       |          |
| Bulletin recommends |   |            |   |         |       |          |
| procedures for      |   |            |   |         |       |          |
| selecting,          |   |            |   |         |       |          |
| designing, and      |   |            |   |         |       |          |
| construction of     |   |            |   |         |       |          |
| diamond grinding in |   |            |   |         |       |          |
| Portland cement     |   |            |   |         |       |          |
| concrete pavements. |   |            |   |         |       |          |
| Diamond grinding    |   |            |   |         |       |          |
| consists of         |   |            |   |         |       |          |
| removing surface    |   |            |   |         |       |          |
| irregularities from |   |            |   |         |       |          |
| concrete pavements  |   |            |   |         |       |          |
| that are often      |   |            |   |         |       |          |
| caused by faulting, |   |            |   |         |       |          |
| curling, and        |   |            |   |         |       |          |
| warping of the      |   |            |   |         |       |          |
| slabs. The main     |   |            |   |         |       |          |
| benefits of         |   |            |   |         |       |          |
| properly using this |   |            |   |         |       |          |
| technique include   |   |            |   |         |       |          |
| smoother ride,      |   |            |   |         |       |          |
| reduced road noise, |   |            |   |         |       |          |
| and improved        |   |            |   |         |       |          |
| friction. Diamond   |   |            |   |         |       |          |
| grinding can be     |   |            |   |         |       |          |
| used as a           |   |            |   |         |       |          |
| stand-alone         |   |            |   |         |       |          |
| rehabilitation      |   |            |   |         |       |          |
| technique. However, |   |            |   |         |       |          |
| FHWA recommends its |   |            |   |         |       |          |
| use as part of a    |   |            |   |         |       |          |
| comprehensive       |   |            |   |         |       |          |
| Concrete Pavement   |   |            |   |         |       |          |
| Rehabilitation      |   |            |   |         |       |          |
| (CPR) program.      |   |            |   |         |       |          |
| Information         |   |            |   |         |       |          |
| regarding cost and  |   |            |   |         |       |          |
| performance is also |   |            |   |         |       |          |
| included in this    |   |            |   |         |       |          |
| document.           |   |            |   |         |       |          |
|                     |   |            |   |         |       |          |
| This document has   |   |            |   |         |       |          |
| been prepared in    |   |            |   |         |       |          |
| part with           |   |            |   |         |       |          |
| information         |   |            |   |         |       |          |
| collected under the |   |            |   |         |       |          |
| sponsorship of      |   |            |   |         |       |          |
| FHWA's Special      |   |            |   |         |       |          |
| Project 205,        |   |            |   |         |       |          |
| Quality Concrete    |   |            |   |         |       |          |
| Pavement            |   |            |   |         |       |          |
| Rehabilitation.     |   |            |   |         |       |          |
| Other documents to  |   |            |   |         |       |          |
| provide similar     |   |            |   |         |       |          |
| guidance in other   |   |            |   |         |       |          |
| CPR techniques will |   |            |   |         |       |          |
| follow.             |   |            |   |         |       |          |
+---------------------+---+------------+---+---------+-------+----------+
| 17\. Key Words      |   |            | 1 |         |       |          |
|                     |   |            | 8 |         |       |          |
| Concrete Pavement   |   |            | \ |         |       |          |
| Rehabilitation,     |   |            | . |         |       |          |
| CPR, Diamond        |   |            | D |         |       |          |
| Grinding, Pavement  |   |            | i |         |       |          |
| Smoothness, Ride    |   |            | s |         |       |          |
|                     |   |            | t |         |       |          |
|                     |   |            | r |         |       |          |
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|                     |   |            | n |         |       |          |
|                     |   |            | s |         |       |          |
+---------------------+---+------------+---+---------+-------+----------+
| 19\. Security       | 2 |            |   | No. of  |       | 22\.     |
| Classification      | 0 |            |   | Pages   |       | Price    |
|                     | \ |            |   |         |       |          |
| (of this report)    | . |            |   |         |       |          |
| None Unclassified   | S |            |   |         |       |          |
|                     | e |            |   |         |       |          |
|                     | c |            |   |         |       |          |
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|                     | l |            |   |         |       |          |
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|                     | N |            |   |         |       |          |
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|                     | e |            |   |         |       |          |
|                     | d |            |   |         |       |          |
+---------------------+---+------------+---+---------+-------+----------+

**NOTICE:** This publication is disseminated under the sponsorship of
the Department of Transportation in the interest of information
exchange. The brochure does not constitute a standard, specification or
regulation. The United States Government does not endorse products or
manufacturers. Trade or manufacturers' names may appear in this
publication only because they are considered essential to the object of
this publication

**Concrete Pavement Rehabilitation**

**Guide for Diamond Grinding**

##### Table of Contents

[INTRODUCTION 3](#introduction)

[DESIGN CONSIDERATIONS 6](#design-considerations)

[Diamond Grinding in the CPR Program
6](#diamond-grinding-in-the-cpr-program)

[Selection of Candidate Projects 7](#selection-of-candidate-projects)

[Equipment 10](#section)

[CONSTRUCTION 12](#construction)

[Traffic Control 12](#traffic-control)

[Field Operations 12](#field-operations)

[PERFORMANCE AND COST 14](#performance-and-cost)

[Performance of Diamond Ground Pavements
14](#performance-of-diamond-ground-pavements)

[Cost of Diamond Grinding 15](#cost-of-diamond-grinding)

[ACKNOWLEDGEMENT 16](#acknowledgement)

[REFERENCES 16](#references)

[BIBLIOGRAPHY 16](#bibliography)

[APPENDIX 18](#appendix)

[Generic Guide Specifications 18](#generic-guide-specifications)

## INTRODUCTION

Diamond grinding is a concrete pavement restoration technique that
corrects irregularities such as faulting and roughness on concrete
pavements. Diamond grinding should be used in conjunction with other
Concrete Pavement Rehabilitation (CPR) techniques. A full CPR job can
restore structural and functional capacity of a pavement to acceptable
levels for a specific traffic need. Full-depth repair, load transfer
restoration, and in special situations, addition of edge drains and/or
slab stabilization may be appropriately used to restore structural
integrity to the pavement. Partial-depth repair may be used to repair
spalled areas at joints and cracks. Diamond grinding restores
rideability by removing surface irregularities caused by construction
curling, slab warping, faulting, and roughness caused by CPR
construction work. The most immediate effect of diamond grinding is a
significant improvement in the riding smoothness of a pavement.

Another very important effect of diamond grinding is the significant
increase in surface macro-texture and consequent noise reduction and
safety improvement. Safety is improved by a temporary increase in skid
friction resistance and a reduction in the potential for hydroplaning.
Safety may also be improved by grooving the pavement surface. Grooving
consists of cutting deeper channels that provides better drainage of
water between the tires and the pavement surface and thus preventing
skidding and hydroplaning. Grooving is not covered in this technical
guide. For more information about grooving the reader may contact the
International Grooving and Grinding Association at 518-731-7450.

Some of the advantages of a diamond ground pavements and its
construction include:

-   Provides a smooth riding surface that is often as good or better
    than a new pavement. Smooth ride is achieved by removing faulting at
    joints and cracks, removing construction curling and
    moisture-gradient warping of the slabs, and other construction or
    environmental related roughness.

-   Enhances surface texture and friction, consequently reducing road
    noise and improving safety.

-   May reduce accident rates in wet weather conditions by providing
    adequate macrotexture and removing studded tires wheel-path rutting.
    These improvements reduce the potential for small-vehicle
    hydroplaning.

-   Does not significantly affect fatigue life of a pavement.

-   Does not affect material durability unless the coarse aggregate is a
    soft stone subject to polishing.

-   Does not raise the pavement surface elevation.

-   May be applied only where is needed, however, spot grinding is
    generally not recommended.

-   Can be constructed during off-peak hours.

Pavement friction may be improved through grinding by enhancing surface
macrotexture. Adequate macrotexture reduces the potential for
hydroplaning, especially in cases where studded tire wear has produced
"ruts" in the concrete pavement. The increased macrotexture initially
provides high skid numbers, but this improvement may be temporary,
particularly if the pavement contains aggregates susceptible to
polishing. This effect may be offset by properly spacing the diamond saw
blades, creating more land area between the grooves on softer coarse
aggregate.

![](media/image1.jpeg){width="3.7291666666666665in"
height="2.5069444444444446in"}Diamond grinding re-textures worn surfaces
with a longitudinal texture and provides a quieter surface. Diamond
grinding also removes faults by leveling the pavement surface, thus
eliminating the thumping and slapping sound created by faulted joints.
However, the thumping sound may also be related to wide joints, which
will not be affected.

Measurements on highways in Belgium indicate a reduction of up to 5 dbA
in pavement noise levels. Also, there may be a considerable difference
in the frequency of noise, resulting in a more pleasant ride after
diamond grinding. Michigan DOT found an after grinding noise reduction
of up to 5dbA in peak frequencies of 500 Hz and the first harmonic of
1000 Hz (DeFrain 1989). This is particularly true of pavements that were
transversely tined with uniformly spaced groves.

Diamond grinding generally reduces slab thickness by 4 to 6 mm (^3^/~16~
to ¼ in). Since slab thickness is one of the most sensitive factors
affecting cracking performance of concrete pavements, any reduction can
be a concern. A cracking model was used to determine the fatigue life of
jointed plain concrete pavement (Rao, Yu, Darter). The result indicated
that a 5-mm (¼ in) reduction in slab thickness results in about 30
percent reduction in fatigue life if the concrete strength remains
constant. However, long-term strength of concrete is significantly
higher than the design strength, which is typically the 28-day strength.
The strength of conventional concrete after 1 year can be up to 20
percent higher than 28-day strength. If the increase in concrete
strength is considered, the small reduction in slab thickness has
negligible effect on service life. These results suggest that a typical
concrete pavement may be ground up to three times without compromising
its fatigue life. In practice, some States have ground concrete
pavements up to three times without reporting any problems (i.e.,
California and Georgia).

> Not all concrete pavements with excessive roughness or faulting are
> good candidates for diamond grinding. For example, a pavement with
> medium traffic and a roughness IRI (International Roughness Index)
> value above 3 m/km (190 in/mi) may be beyond the window of opportunity
> for cost-effective diamond grinding. In such cases, other procedures
> such as an overlay may be a better alternative to restore the
> pavement's smooth ride. In some cases diamond grinding alone may not
> be enough to address an existing problem. Structural distresses such
> as pumping, loss of support, corner breaks, working transverse cracks,
> and shattered slabs will require repairs before grinding is conducted.
> A high percent of shattered slabs (more than 5 percent) indicates a
> structural deficiency in the pavement. The cause of roughness due to
> faulting needs to be addressed before grinding to avoid its
> redevelopment. Severe levels of material durability problems such as
> D-cracking, reactive aggregate, and freeze and thaw damage indicate
> that diamond grinding is not a suitable restoration technique and that
> a more comprehensive rehabilitation strategy should be used to improve
> the pavement.

## DESIGN CONSIDERATIONS

### Diamond Grinding in the CPR Program

### Selection of Candidate Projects

The long-term effectiveness of diamond grinding depends upon a number of
factors. However, the most significant factors are the condition of the
existing pavement structure, traffic and level of CPR applied. It is
important for the designer to recognize that diamond grinding addresses
functional problems of the pavement only. If the existing pavement is
structurally deficient, an overlay or reconstruction may be more
appropriate. Pavements with moderate to advanced material related
distresses such as alkali-silica reaction or D-cracking are not good
candidates for diamond grinding. The use of diamond grinding in
pavements with severe material related distress may lead to accelerate
pavement failure. However, in some cases when the pavement is in poor
condition, diamond grinding may be used as a short-term solution for a
roughness or poor friction characteristics until a more comprehensive
repair or reconstruction of the pavement can be undertaken.

The selection of a good candidate project for diamond grinding, and CPR
in general, involves both engineering and economics. Construction of a
CPR technique too early may not produce significant improvement.
Likewise, a late stage CPR may produce significant improvement, but at a
very high cost, and may not perform very well. This proper timing for
CPR with diamond grinding is better known as the "window of
opportunity." The "window of opportunity" describes the time frame in a
pavement's life when CPR can be applied effectively and economically.
The best method for determining if a pavement is in this time frame is
by performing annual pavement condition surveys and selecting trigger
and limit values for the application of each CPR technique. Trigger
values indicate when a highway agency should consider diamond grinding
and CPR to restore rideability. Limit values for diamond grinding define
the point when the pavement has deteriorated so much that it is no
longer cost effective to grind. Tables 1 and 2 provide an example of
trigger and limit values for diamond grinding for different type of
pavements and traffic volume levels.

Other factors should be considered when selecting a diamond grinding
project. These factors may include:

-   If there is evidence of severe drainage or erosion problem, normally
    indicated by severe faulting (\> 6 mm, or ¼ in) or pumping, actions
    should be taken to alleviate this problem before grinding.

-   The presence of progressive transverse slab cracking and corner
    breaks in jointed pavements indicate a structural deficiency. Slab
    cracking and faulting will continue after grinding, and will reduce
    the life of the rehabilitation project.

-   Joints and transverse cracks with a load transfer of less than 60
    percent should be retrofitted with dowels prior to diamond grinding
    (see publication FHWA-SA-97-103 for more information on load
    transfer restoration). An effort should be made to restrict total
    deflection of slabs at the joints to less than 0.8 mm
    (^1^/~64~-inch). Slab stabilization can be used to restrict the
    total deflection of slabs.

-   The hardness of the aggregate and depth of cut has a direct
    relationship on the cost of the diamond grinding. Grinding of
    pavements with extremely hard aggregate (such as quartzite) takes
    more time and effort that projects with softer aggregate (such as
    limestone). Projects with harder aggregates are more expensive to
    diamond grind.

-   Significant slab replacement and repair may be indicative of
    continuing progressive deterioration that grinding would not remedy.

Table 1. Trigger Values for Diamond Grinding

<table style="width:100%;">
<colgroup>
<col style="width: 15%" />
<col style="width: 10%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 10%" />
<col style="width: 0%" />
<col style="width: 9%" />
<col style="width: 0%" />
<col style="width: 9%" />
<col style="width: 0%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
</colgroup>
<tbody>
<tr class="odd">
<td></td>
<td colspan="3"><strong>JPCP</strong></td>
<td colspan="6"><strong>JRCP</strong></td>
<td colspan="3"><strong>CRCP</strong></td>
</tr>
<tr class="even">
<td><h4 id="traffic-volumes">Traffic Volumes*</h4></td>
<td><h4 id="high">High</h4></td>
<td><h4 id="med">Med</h4></td>
<td><h4 id="low">Low</h4></td>
<td colspan="2"><h4 id="high-1">High</h4></td>
<td colspan="2"><h4 id="med-1">Med</h4></td>
<td colspan="2"><h4 id="low-1">Low</h4></td>
<td><h4 id="high-2">High</h4></td>
<td><h4 id="med-2">Med</h4></td>
<td><h4 id="low-2">Low</h4></td>
</tr>
<tr class="odd">
<td><p>Faulting mm-avg</p>
<p>(inches avg)</p></td>
<td><p>2.0</p>
<p>(0.08)</p></td>
<td><p>2.0</p>
<p>(0.08)</p></td>
<td><p>2.0</p>
<p>(0.08)</p></td>
<td colspan="2"><p>4.0</p>
<p>(0.16)</p></td>
<td colspan="2"><p>4.0</p>
<p>(0.16)</p></td>
<td colspan="2"><p>4.0</p>
<p>(0.16)</p></td>
<td colspan="3">N.A.</td>
</tr>
<tr class="even">
<td>Skid Resistance</td>
<td colspan="12">Minimum Local Acceptable Levels</td>
</tr>
<tr class="odd">
<td>PSR</td>
<td>3.8</td>
<td>3.6</td>
<td>3.4</td>
<td>3.8</td>
<td colspan="2">3.6</td>
<td colspan="2">3.4</td>
<td colspan="2">3.8</td>
<td>3.6</td>
<td>3.4</td>
</tr>
<tr class="even">
<td><p>IRI m/km</p>
<p>(in/mi)</p></td>
<td><p>1.0</p>
<p>(63)</p></td>
<td><p>1.2</p>
<p>(76)</p></td>
<td><p>1.4</p>
<p>(90)</p></td>
<td><p>1.0</p>
<p>(63)</p></td>
<td colspan="2"><p>1.2</p>
<p>(76)</p></td>
<td colspan="2"><p>1.4</p>
<p>(90)</p></td>
<td colspan="2"><p>1.0</p>
<p>(63)</p></td>
<td><p>1.2</p>
<p>(76)</p></td>
<td><p>1.4</p>
<p>(90)</p></td>
</tr>
</tbody>
</table>

\*Volumes: High ADT\>10,000; Med 3000\<ADT\<10,000; Low ADT \<3,000

Table 2. Limit Values for Diamond Grinding

<table style="width:100%;">
<colgroup>
<col style="width: 15%" />
<col style="width: 10%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 10%" />
<col style="width: 0%" />
<col style="width: 9%" />
<col style="width: 0%" />
<col style="width: 9%" />
<col style="width: 0%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
</colgroup>
<tbody>
<tr class="odd">
<td></td>
<td colspan="3"><strong>JPCP</strong></td>
<td colspan="6"><strong>JRCP</strong></td>
<td colspan="3"><strong>CRCP</strong></td>
</tr>
<tr class="even">
<td><h4 id="traffic-volumes-1">Traffic Volumes*</h4></td>
<td><h4 id="high-3">High</h4></td>
<td><h4 id="med-3">Med</h4></td>
<td><h4 id="low-3">Low</h4></td>
<td colspan="2"><h4 id="high-4">High</h4></td>
<td colspan="2"><h4 id="med-4">Med</h4></td>
<td colspan="2"><h4 id="low-4">Low</h4></td>
<td><h4 id="high-5">High</h4></td>
<td><h4 id="med-5">Med</h4></td>
<td><h4 id="low-5">Low</h4></td>
</tr>
<tr class="odd">
<td><p>Faulting mm-avg</p>
<p>(inches avg)</p></td>
<td><p>9.0</p>
<p>(0.35)</p></td>
<td><p>12.0</p>
<p>(0.5)</p></td>
<td><p>15.0</p>
<p>(0.6)</p></td>
<td colspan="2"><p>9.0</p>
<p>(0.35)</p></td>
<td colspan="2"><p>12.0</p>
<p>(0.5)</p></td>
<td colspan="2"><p>15.0</p>
<p>(0.6)</p></td>
<td colspan="3">N.A.</td>
</tr>
<tr class="even">
<td>Skid Resistance</td>
<td colspan="12">Minimum Local Acceptable Levels</td>
</tr>
<tr class="odd">
<td>PSR</td>
<td>3.0</td>
<td>2.5</td>
<td>2.0</td>
<td>3.0</td>
<td colspan="2">2.5</td>
<td colspan="2">2.0</td>
<td colspan="2">3.0</td>
<td>2.5</td>
<td>2.0</td>
</tr>
<tr class="even">
<td><p>IRI m/km</p>
<p>(in/mi)</p></td>
<td><p>2.5</p>
<p>(160)</p></td>
<td><p>3.0</p>
<p>(190)</p></td>
<td><p>3.5</p>
<p>(222)</p></td>
<td><p>2.5</p>
<p>(160)</p></td>
<td colspan="2"><p>3.0</p>
<p>(190)</p></td>
<td colspan="2"><p>3.5</p>
<p>(222)</p></td>
<td colspan="2"><p>2.5</p>
<p>(160)</p></td>
<td><p>3.0</p>
<p>(190)</p></td>
<td><p>3.5</p>
<p>(222)</p></td>
</tr>
</tbody>
</table>

\*Volumes: High ADT\>10,000; Med 3000\<ADT\<10,000; Low ADT \<3,000

### ![](media/image2.jpeg){width="3.59375in" height="2.4166666666666665in"}

Diamond grinding equipment uses diamond saw blades that are gang mounted
on a cutting head. The three most important aspects of a grinding
machine are the weight of the machine, the horsepower available to the
grinding head, and the grinding head itself. The front wheels of the
equipment will pass over a bump or fault, which is then shaved off by
the centrally mounted cutting head. The rear wheels follow in the smooth
path left by the grinding head. The cutting head typically has a width
ranging from 910 to 970 mm (36 to 38 inches) although newer machines
have widths up to 1200 mm (47 inches). The desired corduroy texture is
produced using a spacing of 164 to 194 diamond blades per meter (50 to
60 per foot) of shaft.

The three factors that a contractor must consider in selecting saw
blades are:

1.  ![](media/image3.jpeg){width="3.2395833333333335in"
    height="1.8854166666666667in"}

2.  Diamond size - diamond size can impact the life, cutting speed, and
    costs of the grinding head. Larger diamond particles are better for
    softer aggregate types, while smaller diamonds are better for harder
    aggregates.

3.  ![](media/image4.png){width="3.2395833333333335in"
    height="2.1458333333333335in"}

![](media/image5.jpeg){width="4.09375in" height="2.7395833333333335in"}

## CONSTRUCTION

### Traffic Control

Diamond grinding operations do not require shutting down adjacent
traffic lanes. Traffic can be maintained on adjacent lanes with no
detrimental effects. A contractor can sequence grinding and CPR work to
enable the pavement to be fully opened for rush hour traffic. However,
an approved traffic control plan is essential for the maximum protection
of the traveling public and the construction crew. Several machines
working together allow a lane to be completed in one pass. This improves
productivity for large projects. On small projects, contractors normally
use only one machine and several passes are made to complete a lane
grinding. The maximum overlap between passes should be 50 mm (2 inches).

### Field Operations

The diamond grinding operation should begin after all repairs, including
slab stabilization, patching, and joint and drainage repairs have been
completed. Grinding should be performed continuously along a traffic
lane for best results. Diamond grinding should begin and end at lines
normal to the pavement centerline. Grinding is always longitudinal
(parallel to lanes). The best direction for performing the grinding
depends on sequencing operations and work zone limitations. The
contractor must select the grinding direction in conjunction with the
State engineer. The direction of diamond grinding will not influence the
smoothness of the resulting profile, the resulting texture or effect on
joints. Grinding should be performed across the entire lane surface to
achieve the highest degree of ride quality, uniform skid resistance, and
uniform appearance. Spot grinding is not recommended.

Grinding specifications may allow for some isolated low areas that were
built into the concrete pavement during construction. Isolated low spots
that measured less than 0.2 m^2^ (2.4 sy) need not be textured.

![](media/image6.jpeg){width="3.0208333333333335in" height="2.15625in"}

The grinding equipment uses water to cool the cutting head. The slurry
or residue resulting form the grinding operations should be continuously
removed from the pavement. All modern diamond grinding equipment contain
on-board wet vacuums to perform the removal function. The slurry should
not be allowed to flow across lanes occupied by the traffic or to flow
into gutters or other drainage facilities. However, in rural areas, the
slurry, a non-hazardous material as defined by the Environmental
Protection Agency, may be deposited directly onto adjacent slopes.

![](media/image7.jpeg){width="3.1562992125984253in"
height="2.104330708661417in"}

## PERFORMANCE AND COST

### Performance of Diamond Ground Pavements

A recent study of diamond grinding has shown excellent performance of
diamond ground surfaces (Rao, Yu, Darter). Survival analysis conducted
to quantify the effectiveness of diamond grinding in extending the
service life of concrete pavement showed that the probability that
diamond-ground pavements will have to be overlaid or reconstructed
before the pavement reaches 30 years of age is less than 15 percent. One
possible explanation for the extension in service life of a diamond
ground pavement is the reduction in dynamic or impact loads on the
pavement, as well as other CPR techniques being applied at the proper
time. Dynamic loading is created when trucks travel across bumps and
dips and bounce vertically on their suspension system. Dynamic loads are
greater than the static load from the weight of the vehicle. This
increases stresses in the pavement materials and consequently may
decrease the pavement life. By providing a smooth surface, diamond
grinding limits the dynamic loading, therefore extending the useful
pavement life. However, as mentioned above, a complete CPR strategy that
addresses structural and fuctional defects (including diamond grinding)
is the best approach to extending the service life of a pavement
cost-effectively.

The same study shows that the probability of a diamond ground surface
will last at least 8 years before requiring another rehabilitation is 98
percent. Therefore, based on the study, a diamond ground surface may be
expected to last at least 8 to 10 years.

After the initial performance period, a diamond ground surface may be
reground to re-achieve acceptable levels of ride and surface texture.
Fatigue analysis results show that a typical concrete pavement may be
ground up to three times without compromising its fatigue life.

Diamond grinding results in a significant increase in surface
macrotexture and corresponding improvement in friction. The improvements
in skid resistance immediately after grinding may be dramatic. However,
the improvement may be temporary, particularly if the pavement contains
aggregate that is succeptible to polishing. An initial decrease in skid
resistance during the first few years after grinding is normally leveled
out at adequate macrotexture levels that are maintained for many years.
Climate and age may be the most significant factors in the rate of
reduction of macrotexture on a diamond-ground surface. Wet-freeze areas
exhibit larger decreases in macrotexture than dry-non-freeze areas. The
sand patch test should be used to determine the macrotexture
characteristics of a diamond ground concrete surface.

### Cost of Diamond Grinding

Diamond Grinding is a cost-effective treatment, wheter used alone or as
part of an overall CPR program. Diamond grinding costs on average
between \$2.00 and \$8.00 per square meter (\$1.70 and \$6.70 per sy).
However, the cost may be higher (up to \$12/m^2^ or \$10/sy) when
concrete contains very hard river gravel. The cost depends on many
factors including aggregate and PCC mix properties, average depth of
removal, and smoothness requirements. The cost of diamond grinding has
dropped in the last few years. Increased competition and better diamond
blade performance may help lower prices even more the future. State
DOT's have found that the cost of diamond grinding is generally lower
than the cost of an asphalt concrete overlay. Much of the cost savings
can be attributed to the fact that diamond grinding can be applied only
to lanes that need the corrective treatment.

Cost-effectiveness makes diamond grinding an important and appealing
alternative for many concrete rehabilitation projects. Diamond grinding
should also be part of any preventive maintenance program for concrete
pavements.

## ACKNOWLEDGEMENT

This document would not have been possible without the assistance and
cooperation of the FHWA's Office of Pavement Technology and the Southern
Resource Center. Part of the information used in preparing this document
was collected as part of the FHWA's Special Project 205, Quality
Concrete Pavement Rehabilitation.

Special thanks to Roger Larson, Keith Herbold, Gregg Schiess, and Phil
Arena from FHWA for their review and comments. Wouter Gulden and John
Roberts from the American Concrete Pavement Association also provided
helpful information and comments on this document.

The contents of this document reflect the views of the authors, who are
responsible for the facts and the accuracy of the data presented.

## REFERENCES

Defrain L., "Noise Analysis of Ground Surface on I-69 WB Near Lowell
Road C.S. 19043", Research Project 88 TI-1342, Office Memorandum,
Michigan DOT, Lansing, Michigan, 1989.

Noise and Texture on PCC Pavement, Results of a Multi-State study, Final
Report WI/SPR-08-99, Marquette University, FHWA and Wisconsin DOT, June
2000.

Rao S., Yu H.T., Darter M.I., "The Longevity and Performance of
Diamond-Ground Pavements", Research & Development Bulletin RD118, PCA,
1999.

## BIBLIOGRAPHY

ACPA Technical Bulletin TB-008 P CPR 'Diamond Grinding', 1990.

Concrete Pavement Restoration, Diamond Grinding, the Georgia Story,
Roads and Bridges Magazine, April, 1996

CPR Issues, Diamond Grinding: A Proven Road to Highway Safety, General
Electric

CPR Issues, Ride Quality: An Acceleration Concern - and Why, General
Electric

Concrete Pavement Restoration, the Cover Up vs. the Concrete Solution.
General Electric, October, 1984

Concrete Paving Technology, the Concrete Pavement Restoration Guide,
ACPA, 1997.

The Effects of Grinding on PCC Pavements, Final Report WI/SPR-11-99,
Wisconsin Department of Transportation, November, 1999.

Tire Pavement Noise and Safety Performance, FHWA-SA-96-068, May 1996.

Federal Highway Administration (FHWA). 1985, 'Pavement Rehabilitation
Manual,' FHWA-ED-88-025, Federal Highway Administration, Washington, DC
(Supplemented April 1986, July 1987, March 1988, February 1989, October
1990).

Federal Highway Administration (FHWA). 1998, 'Techniques for Pavement
Rehabilitation, Reference Manual (Sixth Edition),' FHWA-HI-98-033.

Federal Highway Administration (FHWA). 1990, 'Pavement Notebook for FHWA
Engineers,' FHWA-ED-90-016.

"Texturing and Skid Resistance of Concrete Pavements and Bridge Decks",
Technical Advisory T5140.10, Federal Highway Administration, September
1979 (Currently being updated).

ACPA, Concrete Pavement Restoration Guide, Technical Bulletin TB 020P,
Skokie IL, 1997

ACPA/IGGA, Diamond Grinding and Concrete Pavement Restoration, Technical
Bulletin TB008.01P, Skokie, IL, 2000

Wayson R. L., NCHRP Synthesis 268, "Relationship Between Pavement
Surface Texture and Highway Traffic Noise", TRB, Washington DC, 1998

NCHRP Synthesis 291, "Evaluation of Pavement Friction Characteristics",
TRB, Washington DC, 2000

Drakopoulos A., Wenzel T. H., Shober S. F., Schmiedlin R. B.; "Crash
Experience on Tined and Continuously Ground Portland Cement Concrete
Pavements", TRR 1639, pp 140-146

## APPENDIX 

### Generic Guide Specifications

DIAMOND GRINDING

Description

This specification covers diamond grinding of Portland cement concrete
pavement to eliminate joint faulting, and restore proper drainage and
ride quality. This work shall be accomplished in accordance with these
specifications, the details shown on the plans, and as directed by the
engineer.

Equipment

The grinding equipment shall use diamond tipped saw blades mounted on a
power driven, self-propelled machine that is specifically designed to
smooth and texture PCC pavement. The equipment shall grind the pavement
to the specified texture and smoothness tolerances. The equipment shall
not damage the underlying surface of the pavement, cause excessive
ravels, aggregate fractures, spalls, or otherwise disturb the transverse
or longitudinal joint

Construction

The plans will designate areas of pavement surfaces to be ground.
Grinding of roadway shoulders and bridge decks will not be required
unless indicated on the plans, or is directed by the engineer. Grinding
shall be performed in a longitudinal direction and shall begin and end
at lines normal to the pavement centerline in any ground section.
However, this is not required at the end of each work shift.

The grinding shall produce a uniform finished surface, eliminate joint
or crack faults, and provide positive lateral surface drainage.
Auxiliary or ramp lane grinding shall transition as required from the
mainline edge to maintain or provide positive lateral drainage and an
acceptable riding surface.

Grinding will provide a positive lateral drainage by maintaining a
constant cross slope across each lane. The entire area designated on the
plans shall be textured and surfaces on both sides of the transverse
joints or cracks shall be in essentially the same plan, in accordance
with smoothness specifications. A 1 by 30-meter (3-foot x 100-foot) test
area shall require 95% coverage. However, extra depth grinding to
eliminate minor depressions is not required.

The slurry or residue resulting from the grinding operations shall be
continuously removed from the pavement. The slurry shall not be allowed
to flow across lanes occupied by traffic or to flow into gutters or
other drainage facilities. However, in rural areas it may be deposited
directly onto adjacent slopes.

Final Surface Finish

The ground pavement surface shall be uniform in appearance with
longitudinal corduroy type texture. The grooves shall be between 2 and 4
mm (0.10 and 0.15 inches) wide. The land area between the grooves shall
be between 1.5 and 3.5 mm (0.065 and 0.125 inches). The peak of the
ridges shall be approximately 1.5 mm (1/16 inch) higher than the bottom
of the grooves. Adjusting the blade spacing may be necessary to achieve
the specified texture.

The ground pavement shall meet a surface tolerance at least as stringent
as the specifying agency's surface tolerance for new pavement. The
pavement surface shall be measured for riding quality using a multiple
wheel profilograph or a profiler. If a profilograph is used, the
pavement is to be evaluated in 1.6 km (0.1 mile) sections. When using a
profilograph, the profile index shall not exceed 40 inches per mile for
a **0.0** blanking band. A unit price adjustment may be used for a
profile index of 40 to 50 inches per mile in lieu of re-grinding to meet
the 40 inches per mile criterion. No payment will be made for a profile
index in excess of 50 inches per mile. The profiler tolerance will be
the same as the agency's surface tolerance for new pavement.

A straight-edge requirement may be used to control bumps and/or rides in
the pavement surface. Grinding along the inside edge of existing
pavement shall conform to the highway agency's straight-edge
requirement. Straight-edge requirements do not apply across longitudinal
joints or outside the ground areas. The transverse slope of the pavement
shall be uniform to a degree that there shall be no depressions or
misalignment of slope greater than 1/8 inch between passes of the
cutting head when tested by stringline or straight-edge placed
perpendicular to the centerline. Transverse joints and random cracks
shall be visually inspected to insure that adjacent surfaces are in the
same plane. Misalignment of the planes of these surfaces shall not
exceed 1.5 mm per meter (1/16 inch in 3 feet).

Traffic Control

The contractor shall provide all traffic control devices necessary for
maximum protection of the traveling public and construction work area
with only a minimum of interference. Unless otherwise specified, the
contractor shall prepare and submit in advance, a written traffic
control plan in accordance with Part VI of the [Manual of Uniform
Traffic Control]{.underline} [Devices]{.underline} current edition, for
review and approval by the engineer.(10)

Measurement

Pavement grinding shall be measured by the square meter (square yard),
ground to any depth. The quantity of work is determined by multiplying
the width by the length of ground areas.

Payment

Pavement grinding will be paid for at the contract price per square
yard. Payment is full compensation for furnishing all labor, materials,
supplies, tools, equipment, any incidental work, and for doing all work
involved in grinding and texturing the pavement and shoulders and
cleaning the pavement.

Traffic control will be paid for under the separate pay items for the
project. Traffic control will include all devices and requirements as
stated in the traffic control section.