306GEOGRID BASE REINFORCEMENT

249 TABLE 305 -2 ADJUSTMENT IN CONTRACT UNIT PRICE FOR DEFICIENCY IN COMPRESSIVE STRENGTH OF LEAN CONCRETE BASE Notes: *Material represented by cores deficient by more than 0.75 inches in thickness and/or represented by lots attaining seven- day compressive strengths with the mean value of the four compressive strength tests less than 350 pounds per square inch will be evaluated as to acceptance. The Engineer will determine if the material can be left in place. Lean concrete base allowed to remain in place will be subject to the unit price adjustments presented in Tables 305- 1 and 305- 2. Lean concrete base not permitted to remain in place shall be removed and replaced at no additional cost to the Department. **The Unit Price Adjustment will be multiplied by the design thickness of lean concrete base in inches, the product divided by 10, and rounded off to the nearest 25 cents to determine the unit price for payment. 306- 1 Descripti on: The work under this section shall consist of furnishing and placing a geogrid material within and/or below the aggregate base in accordance with the requirements of the specifications and as shown on the project plans. 306- 2 Materials: 306- 2.01 Geogrid Materials: The geogrid material shall be supplied in accordance with and conform to the material requirements of Subsections 1014- 1 and 1014- 3 of the specifications. 306- 2.02 Geogrid Packaging, Handling, and Storage: The identification, packaging, handling, and storage of the geogrid material shall be in accordance with ASTM D4873. Geogrid rolls shall be furnished with suitable wrapping for protection from the elements, primarily ultraviolet exposure, prior to placement. Each roll shall be labeled or tagged to provide product identification sufficient to determine the product type, manufacturer, quantity, lot number, roll number, date of manufacturer, shipping date, and the project number and name to which it is assig ned. Rolls will be stored on the site or at another identified storage location in a manner which protects them from the elements, and any other factor which may cause damage to the TABLE OF CONTENTS INDEX 250 material. Care should be taken to prevent mud, wet cement, epoxy, and other contaminating materials which may permanently affix themselves to the grid material, from coming into contact with the geogrid. If stored outdoors, geogrid rolls shall be elevated and protected with a light colored, opaque, and waterproof cover. At no time shall the geogrid material be exposed to ultraviolet light for a period exceeding 14 days or stored in temperatures below 0 degrees F or in extreme heat. Torn, damaged, or defective geogrid will be rejected. 306- 3 Construction Requirements: 306- 3.01 Weather Limitations: The geogrid shall not be placed when weather or surface conditions, in the opinion of the Engineer, are not suitable for placement. This will normally be at times of wet and snowy conditions, heavy rainfall, extreme cold or frost conditions, or extreme heat. 306- 3.02 Equipment: Mechanical or manual laydown equipment shall be capable of laying the geogrid properly and smoothly, according to the manufacturer's recommendations. 306- 3.03 Surface Preparation: If the geogrid material is to be placed directly on the subgrade, the subgrade surface shall be compacted and finished according to Subsections 203- 3.03, 203- 10.03, or 205- 3.04 of the specifications prior to placement of the geogrid. If the geogrid material is to be placed within the aggregate base materials, the aggregate base surface upon which the geogrid will be placed, shall be compacted according to Subsection 303- 3.02 of the specifications and finished according to Subsection 303- 3.03 of the specifications before placement of t he geogrid. 306- 3.04 Geogrid Placement: The geogrid shall be rolled out along the alignment in the direction of advancing construction. All wrinkles and folds shall be removed. A 12 -inch minimum overlap is required at all transverse and longitudinal joints. The center of a longitudinal overlapped joint in a geogrid layer shall be staggered a minimum of 1 foot with relation to the center of a longitudinal overlapped joint in any immediate underlying geogrid layer. TABLE OF CONTENTS INDEX 251 The center of a longitudi nal overlapped joint in a geogrid layer below an asphaltic concrete pavement shall be located within 1 foot of the center of a lane or within 1 foot of the centerline between two adjacent lanes. At transverse joints, the top layer of the geogrid shall over lap the lower layer of geogrid in the direction that the aggregate base will be placed. The geogrid shall be tensioned by hand and anchored to the ground with securing pins at the edges, including overlaps, and in the center of the roll at 30- foot intervals along the roll length, at the corners if applicable, or as directed by the Engineer. Securing pins shall be 3/16- inch diameter steel bars, with a minimum length of 4 inches, pointed at one end and fabricated with a head to retain a steel washer having an outside diameter of not less than 1.5 inches. Alternatively, U -shaped pins may be used if approved by the Engineer. The use of securing pins may be reduced or eliminated by the Engineer if it can be shown that by careful installation the geogrid is adequately tensioned by hand and anchored by the placed aggregate in a progressive installation process as recommended by the manufacturer's representative. Care shall be taken to ensure that geogrid sections do not separate at overlaps during construction. Placement of geogrid around corners will require cutting of the geogrid product and diagonal overlapping of the same to make sure that excessive buckling of geogrid material does not occur. 306- 3.05 Placing and Compacting Aggregate Fill: The aggregate shal l be back dumped and spread in a uniform lift maintaining the design aggregate thickness at all times. The aggregate material shall be bladed onto the geogrid in such a manner that the aggregate rolls onto the grid ahead, by gradually raising the dozer bl ade while moving ahead. If the underlying material is capable of supporting rubber tire trucks (end and belly dumps) they may drive over the grid at very low speeds, less than five miles per hour, and dump aggregate as they go. Sudden stops and turning by trucks shall be avoided while on the grid. No tracked vehicles shall be allowed on the grid until there is a minimum of 6 inches of material between the tracks and the grid. Any ruts which might develop during spreading or compacting the aggregate shall be filled with additional aggregate rather than bladed from surrounding areas. Placing additional aggregate into the rutted areas ensures that the design aggregate thickness is maintained. Geogrid damaged after or during construction will be repaired in accordance with the manufacturer's recommended procedure. Aggregate base shall be compacted as specified in Subsection 303- 3.02 of the specifications. Aggregate base material shall not be mixed or TABLE OF CONTENTS INDEX