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REVISION REQUEST 4036

106.3.2.93.1 Means of Evaluating Aggregate Alkali Carbonate Reactivity

1. Chemical Analysis

The chemical analysis of aggregate reactivity is an objective, quantifiable and repeatable test. MoDOT will perform the chemical analysis per the process identified in ASTM C 25 for determining the aggregate composition. The analysis determines the calcium oxide (CaO), magnesium oxide (MgO), and aluminum oxide (Al2O3) content of the aggregate. The chemical compositions are then plotted on a chart with the CaO/MgO ratio on the y-axis and Al2O3 percentage on the x-axis per Fig. 2 in AASHTO R 80. Aggregates are considered potentially reactive if the Al2O3 content is greater than or equal to 1.0% and the CaO/MgO ratio is either greater than or equal to 3.0 or less than or equal to 10.0 (see chart below). See flow charts in 106.3.2.93.2 for approval hierarchy. CaO, MgO and Al2O3 shall be analyzed by instrumental analysis only.

* MoDOT’s upper and lower limits of potentially reactive (shaded area) aggregates.

2. Petrographic Examination

A petrographic examination is another means of determining alkali carbonate reactivity. The sample aggregate for petrographic analysis will be obtained at the same time as the source sample. MoDOT personnel shall be present at the time of sample. The petrographic sample shall be placed in an approved tamper-evident container (provided by the quarry) for shipment to petrographer. Per ASTM C 295, a petrographic examination is to be performed by a petrographer with at least 5 years of experience in petrographic examinations of concrete aggregate including, but not limited to, identification of minerals in aggregate, classification of rock types, and categorizing physical and chemical properties of rocks and minerals. The petrographer will have completed college level course work in mineralogy, petrography, or optical mineralogy. MoDOT does not accept on-the-job training by a non-degreed petrographer as qualified to perform petrographical examinations. MoDOT may request petrographer’s qualifications in addition to the petrographic report. The procedures in C 295 shall be used to perform the petrographic examination. The petrographic examination report to MoDOT shall include at a minimum:

  • Quarry name and ledge name; all ledges if used in combination
  • MoDOT District quarry resides
  • Date sample was obtained; date petrographic analysis was completed
  • Name of petrographer and company/organization affiliated
  • Lithographic descriptions with photographs of the sample(s) examined
  • Microphotographs of aggregate indicating carbonate particles and/or other reactive materials
  • Results of the examination
  • All conclusions related to the examination

See flow charts in EPG 106.3.2.93.2 for the approval hierarchy. See EPG 106.3.2.93.3 for petrographic examination submittals. No direct payment will be made by the Commission for shipping the petrographic analysis sample to petrographer, or for the petrographic analysis performed by the petrographer.

3. Concrete Prism/Beam Test

ASTM C 1105 is yet another means for determining the potential expansion of alkali carbonate reactivity in concrete aggregate. MoDOT will perform this test per C 1105 at its Central Laboratory. Concrete specimen expansion will be measured at 3, 6, 9, and 12 months. The test specimens will be considered alkali carbonate reactive (expansive) if the specimens expand greater than 0.015% at 3 months, 0.025% at 6 months, or 0.030% at 12 months. See flow chart in EPG 106.3.2.93.2 for the approval hierarchy.

REVISION REQUEST 4060

902.5.43 Power Outages at Signalized Intersections

Guidance. Each District should plan for signalized intersection power outages by developing procedures for signalized intersections that include information about the installation, use, and recovery of Temporary Stop Signs (TSS) and, if used, the installation of battery backup systems. These subarticles provide information for these items.

902.5.43.1 Temporary Stop Signs at Signalized Intersections

Support. Temporary Stop Signs (TSS) refer to stop signs that meet the MUTCD stop sign design requirements for regulatory signs and are temporarily installed at signalized intersections where the traffic signals cannot function due to damage and/or power outage. These temporary placements include but are not limited to roll-up stop signs, temporary mounts on the signal vertical upright, or stop signs mounted on other crash worthy devices.

Standard. Utilities or other non-MoDOT parties doing planned permitted work that will cause a power outage leading to a non-functioning signalized intersection(s) shall be responsible for providing the necessary TSS or generator(s) to power the signalized intersection(s) until power at the non-functioning signalized intersection(s) has been restored.

902.5.43.1.1 Conditions For Use

Option. TSS may be erected at locations where a signalized intersection is non-functioning. A non-functioning signalized intersection is defined as an intersection that is equipped with a traffic signal that is damaged and/or without power which cannot display proper indications to control traffic. When a signalized intersection is non-functioning, then TSS may be installed when one of the following conditions is met:

  • When the traffic signal is both damaged and without power, or
  • When the traffic signal is without power and restoration of power using an alternate power source is not possible.

Guidance. After verifying that the signal is non-functioning, Districts should contact the appropriate utility company to notify them of the power outage, if applicable, and to determine if power will be restored in a reasonable amount of time (at the District’s discretion). If used, the TSS should be deployed as soon as practical depending on location of the signalized intersection and the stored TSS. Districts should also request police assistance for traffic control if they are not already present at the site or aware of the power outage. Outside of normal business hours, it might be necessary for the electrician or maintenance personnel to directly contact the highway patrol or local police and the power company.

Standard. When TSS are utilized at a signalized intersection that is non-functioning, the District shall decide whether the power shall be disconnected or whether the signal should be switched to flash to avoid conflicts when power is restored. If switched to flash, the flash shall be red-red since TSS will be installed on all approaches, if used, at a signalized intersection without power (dark signals are to be treated like a 4-way stop according to the Missouri Driver’s Guide). The TSS shall not be displayed at the same time as any signal indication is displayed other than a flashing red.

A request shall be made of the nearest maintenance building, emergency responder, or external emergency responder (whomever stores the TSS) to bring stop signs to the intersection. Personnel or emergency responders instructed in signal operation shall disconnect the power or switch the signal to flash operation (external emergency responders will do this in the signal cabinet police door) before placing the TSS. Without this change in operation, the traffic signal could return to steady (stop-and-go) mode within seconds after the signal is repaired or power is restored, which would cause conflicts between the signal and the TSS (conflicting green or yellow indications with a stop sign for the same approach). The signal shall be visible to traffic on all approaches and all these approaches will flash upon restoration of power (see EPG 902.5.43.2 for more information regarding Startup from Dark).

If used, TSS signs shall remain at the intersection until power at the non-functioning signalized intersection has been restored (see EPG 902.5.43.1.4 Recovery).

Guidance. When law enforcement is present at a non-functioning signalized intersection to direct traffic, then the TSS that have been placed should be covered or removed to avoid conflicts (the law enforcements authority supersedes the TSS).

Option. If it has been determined that the power outage will last for an extended amount of time (at the District’s discretion) the signal heads may be covered to reduce the confusion of approaching motorists.

Guidance. If signal heads are covered, the appropriate enforcement agency should be advised and asked to occasionally monitor the intersection. Also, the power company should be advised and asked to notify proper personnel when the power is restored.

902.5.43.1.2 Location and Placement

Standard. The signalized intersection locations for installation of TSS shall meet the conditions of use in EPG 902.5.43.1.1 and shall be at the discretion of the District.

Option Each District may develop a list of signalized intersections to establish a priority for TSS installation.

Guidance. The installation of TSS should be prioritized as follows (as applicable to each district) or, if a list is developed, should begin at the identified intersections:

  1. Signals with railroad preemption
  2. Signals with a speed limit greater than 50 mph
  3. Signals with a high accident rate
  4. Intersections difficult to flag or require multiple flaggers (non-routine roadway configurations/geometry, SPUIs, multi-lane approaches, etc.)
  5. Signals with high volumes (freeway type off-ramps, major roadways, etc.)
  6. Signals with frequent power outages
  7. Signals located at schools.

If battery backup systems are installed (see EPG 902.5.43.3 Battery Backup Systems at Signalized Intersections) at signalized intersections, Districts should re-evaluate their list of prioritized intersections, if developed, for the installation of TSS.

Standard. When used, TSS shall be placed in a location where they are visible to all lanes on all roadways. On two-way roadways, stop signs shall be erected on the right-hand side of all approaches. On divided highways, stop signs shall be erected on both the right and, if possible, on the left-hand side or at location for best visibility of all approaches.

Guidance. If the power outage is widespread, additional personnel should be requested to help with the placement of the signs.

902.5.43.1.3 Storage and Distribution

Guidance. Each District should store enough TSS to be deployed at high priority signalized intersections.

Standard. TSS shall be distributed by the District to the District’s maintenance personnel or emergency responders or external emergency responders on an as-needed basis. It shall be the responsibility of the District to develop a means of distribution.

902.5.43.1.4 Recovery

Standard. TSS shall remain at the intersection until power at the non-functioning signalized intersection has been restored. Power will remain disconnected or the signal will flash until TSS are removed. Immediately following TSS removal, personnel or emergency responders instructed in signal operation shall restore signal operation in accordance with the procedures set forth in EPG 902.5.43.2 Steady (stop-and-go) Mode for transition to steady (stop-and-go) mode.

The recovery of the TSS shall be accomplished by using the District’s maintenance personnel or emergency responders or external emergency responders by either of the following:

  • Complete removal from each intersection.
  • Stockpiling outside of the intersection to avoid conflicts with the signalized intersection (stockpiled signs shall not be faced towards the traveling public and stored not to damage sheeting) and stored in a location to not become a roadside hazard.

Option. Detailed recovery procedures for each intersection with TSS may be developed by each District at their discretion.

902.5.43.2 Start up from Dark at Signalized Intersections

Standard. When a signalized intersection has been damaged and/or is without power the District shall have either disconnected the power or switched the signal to flash to avoid conflicts when power is restored. If switched to flash, the flash shall be red-red since TSS will be installed on all approaches, if used, at a signalized intersection without power (dark signals are to be treated like a 4-way stop according to the Missouri Drive’s Guide). If TSS are in place, the power shall remain disconnected or the signal shall operate in flash mode until TSS are removed and personnel or emergency responders instructed in signal operation restore signal operation.

Steady (stop-and-go) Mode

Standard. When power is reconnected or when the signal is switched from flash to steady (stop-and-go) mode, the controllers shall be programmed for startup from flash. The signal shall flash red-red for 7 seconds and then change to steady red clearance for 6 seconds followed by beginning of major-street green interval or if there is no common major-street green interval, at the beginning of the green interval for the major traffic movement on the major street.

902.5.43.3 Battery Backup Systems at Signalized Intersections

902.5.43.3.1 Installation/Placement

Option. Battery Backup Systems (BBS) may be installed at signalized intersections at the District’s discretion. Each District may develop a list of signalized intersections to establish a priority for the installation of BBS.

Guidance. The installation of BBS should be prioritized as follows (as applicable to each District) or, if a list is developed, should begin at the identified intersections:

  1. Signals with railroad preemption
  2. Signals with a speed limit greater than 50 mph
  3. Signals with a high accident rate
  4. Intersections difficult to flag or require multiple flaggers (non-routine roadway configurations/geometry, SPUIs, multi-lane approaches, etc.)
  5. Signals with high volumes (freeway type off-ramps, major roadways, etc.)
  6. Signals with frequent power outages
  7. Signals located at schools.

If developed, each District’s prioritized installation list for BBS should be based on their traffic conditions and needs. The prioritized TSS installation list, if developed, will need to be reevaluated as BBS are installed.

902.5.43.3.2 Duration

Standard. BBS shall be capable of operating at a minimum of 2 hours in steady (stop-and-go) mode and a minimum of 2 hours in flash operation.

Guidance. Any signalized intersection with BBS should have a generator socket for extended operation.


REVISION REQUEST 4094

941.6.3.6 Deposit Requirements

Deposits are not routinely required for applicants constructing Type I (private residential/farm) entrances, however unusual conditions or construction may warrant a deposit. Deposits may be required for Type II (side street/road), Type III, Type IV, and Type V (commercial/industrial) entrances if the applicant is not a government agency. Details regarding entrance types, refer to the standard plans.

In order to maintain consistent deposit requirements for entrance permits, the cost of curbing required is used as a guide. If other circumstances or construction dictate the need to increase the deposit above the amount required to build the curbing, this increased amount is added to the deposit.

If the deposit is a cashier’s check, a minimum amount of $500 and a maximum of $50,000 will be required. If deposit requirements exceed $50,000, a performance bond will be required. There is no maximum limit for a performance bond. The performance bond or cashier's check shall be made payable to Director of Revenue - Credit State Road Fund.

All deposit checks shall be transmitted to Financial Services using the following procedure:

  1. Forward deposit as received to Financial Services by attaching the Receipt - Transmittal of Money form. It is imperative to furnish the remitter’s correct name and address.
  2. Upon satisfactory completion of the permit, the district advises Financial Services by email or other written communication to refund a check to the remitter.
  3. Financial Services will transmit the check directly to the remitter and also notify the district by email that the check has been processed. The warrant request is attached to the file copy of the permit.
  4. If the work is not completed as described in the permit, refer to Default of Permit Requirements.

Performance bonds for permits to work on Missouri Highways and Transportation Commission (MHTC) right of way should use the table below to determine minimum performance bond amounts. All bond amounts should be discussed with a MoDOT representative. MoDOT reserves the right to adjust any performance bond amount at any time.

Number of Permits per Year Minimum Bond Amount
24 $120,000.00
40 $200,000.00
60 $300,000.00
100 $500,000.00


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