(A) Density tests on subgrades and base courses shall be taken every 300 feet or portion thereof, except that each cul-de-sac street shall have a minimum of two tests taken regardless of its length. The subgrade shall be compacted to 95% of Standard Proctor (AASHTO T99 Method A or C). The base course shall be compacted to 95% of Modified Proctor (AASHTO T180 Method D) on local streets and higher classified streets. Base course placed under curb and gutter that is four inches or less in thickness will not require density test but will require “proof rolling”. Minimum base course thickness for local and higher classified streets is eight inches. For concrete streets the minimum base course required is three inches. Base course shall not be more than 1/4 inch less than specified thickness. Random soundings will be performed to ensure thickness is achieved. Rectification for base course which does not meet tolerance shall be submitted by engineer of record for review and consideration by City Engineer. Remedial work will be at the discretion of the City Engineer.
(B) Asphalt streets shall be cored every 300 feet or portion thereof for the purpose of checking density and thickness, except that each cul-de-sac street shall have a minimum of two cores taken regardless of length, with one being taken within the cul-de-sac. The location of the core shall be chosen by the City Engineer or his or her designated representative so as to accurately represent the quality of the asphalt laid in a particular area. Lanes of streets laid on different days may be required to have additional cores at City Engineer’s discretion. Core samples shall be used to indicate asphalt thickness, and in no case shall be more that 1/4 inch less than specified thickness. For cores that indicate thickness 1/4 inch to 1/2 inch less than that specified, isolation cores will be required. To isolate, the contractor, at no expense to the city, shall cut cores ten feet either side of the initial core. If one or both of the cores are in the acceptable tolerance, the section will be accepted. If one or both cores fail, then additional cores will be cut 25 feet away from the initial core in the failing directions. Subsequent cores will be cut at 50 foot intervals in the direction of failure until a core that passes tolerance is obtained. The isolated area will be that which falls within the limits of acceptable thickness. The areas that fall within the 1/4 inch to 1/2 inch less than specified thickness may be removed and replaced or warranted for five years at 150% of construction cost based on the estimate provided by the engineer of record. Areas that are determined to exceed the ½ inch less than specified thickness shall be removed and replaced within the limits of the acceptable thickness determined by the isolation method.
(C) Minimum asphalt density for black base, binder, and surface courses shall be 92.0% of the maximum theoretical density. Maximum asphalt density for black base, binder and surface courses shall be 96% of maximum theoretical density. Asphalt densities that fall between 90% to 92% and 96% to 98% shall be left in place and an extended warranty of five years at 150% of construction cost based on the estimate provided by the engineer of record will be required on the deficient asphalt pavement. Where densities are less than 90% or greater than 98%, the paving shall be removed and replaced. The limits of the deficient asphalt pavement shall be determined by the isolation method by first cutting two cores within two feet each side of the failing core, then add the results of the density of the original core and the two additional core densities. Divide by three and if the average of the three core densities fall within the acceptable ranges as specified above, then that section will be accepted per the aforementioned requirements. If the average of the original and the two re-cores fall below acceptable range, then additional cores will be cut first going 25 feet longitudinally in each direction from the original core and determining the densities of each. A resulting failing core from that point will require an additional core being cut 50 feet from that previous core and will continue in 50 foot increments until a passing core density is obtained. The failed area will consist of the area falling within the limits of the passing re- cores and will be addressed per the aforementioned requirements.
(D) Minimum thickness of local concrete streets shall be six inches and minimum 28 day compressive strength shall be 3,500 psi. A formal pavement design is required for higher classified streets but in no case shall be less than six inches in depth. A set of cylinders shall be taken for each 100 cubic yards or portion thereof poured. Admixtures for concrete pavement shall be approved by the City Engineer prior to placement.
(E) Concrete for curb and gutters shall be a minimum 28 day compressive strength of 3,500 psi. One set of cylinders shall be taken at beginning of pour then for every 1,000 linear feet of curb and gutter poured, or portion thereof.
(F) Concrete streets shall be cored every 300 feet or portion thereof for the purpose of checking thickness. Thickness shall not be more than 0.50 inches deficient. Areas of more than 0.50 inches deficiency shall be removed and replaced. The city may at its sole discretion choose to leave the deficient concrete slab in place and accept an extended five year warranty for concrete placement at 150% of construction costs based on estimate provided by the engineer of record.
(G) Concrete testing out less than 85% of design strength shall be removed and replaced. For concrete falling between 85% and 100% of design strength, an extended five year warranty for concrete placement shall be provided at 150% of construction costs based on estimate provided by the engineer of record.
(H) All core test holes for concrete and asphalt streets shall be filled with non-shrink grout flush with final surface within 24 hours of test.
(Ord. 2009-11-347, passed 11-3-09; Am. Ord. 2010-06-356, passed 6-1-10; Am. Ord. 2018-11-816, passed 11-6-18)