1. Use limited to bedding concrete over which backfill will be placed not less than 40 hours after placement. For backfill after 24 hours, add 3 pints of calcium chloride. For backfill after 16 hours and removal of sheeting after 18 hours, use 660-C-3750 with 3 pints calcium chloride solution.

2. Use B Aggregate gradation when placing conditions permit.

3. 4000 psi concrete mixes require the use of a water reducing admixture conforming to the requirements of 201-1.2.4, "Admixtures."

4. Concrete mixes followed by a "P" have been designed to accommodate placement by a concrete pump. A pump mix may be substituted for a similar class mix and placed utilizing standard placement methods by the Contractor at its option. Said substitution, if made, shall be at the Contractor's expense.

5. Concrete mixes followed by a "G" have been designed to accommodate the grout requirements of Section 202, Masonry Materials.

When approved by the Engineer, trial batches may be placed in the Work at designated locations where concrete of a lower quality is specified. Concrete so placed will be considered for purpose of payment to be the type of concrete specified at that location.

Ten test cylinders shall be molded from the trial batch containing the maximum water content indicated by the mix design. Five of the cylinders shall be tested at 7 days in order to establish 7-day average compressive strength information. The remaining five cylinders shall be tested at no more than 28 days after molding and the average compressive strength of the five cylinders shall be at least 600 psi greater than the specified strength. The minimum strength of any one cylinder shall not be less than the specified strength. The placing of concrete specified by compressive strength shall not begin until the mix design has qualified in accordance with aforesaid test criteria. Should the source of materials or established procedures change, new trial batches may be required.

201-1.1.4 Test for Portland Cement Concrete. Portland cement concrete shall be sampled and tested in accordance with the following ASTM and California Tests:

A compressive strength test shall consist of the average strength of two cylinders fabricated from a single load of concrete, except that if any cylinder shows evidence of improper handling, molding, or testing, it shall be discarded and the strength test shall consist of the strength of the remaining cylinder.

The frequency of sampling will be determined by the Engineer. The Contractor shall afford the Engineer all reasonable access, without charge, for the procurement of samples of fresh concrete at time of placement.

Concrete compressive strength tests representing concrete which has been placed shall attain the following 28-day strength: The average of any three consecutive strength tests shall be equal to or greater than the specified 28-day strength. Not more than 10 percent of the tests shall be less than the specified 28-day strength. No test shall be less than 85 percent of the specified 28-day strength.

Concrete represented by compressive strength tests which fails to meet the requirements of this subsection shall be removed from the Work. However, with approval of the Engineer, the concrete represented by the failing compressive strength tests may be cored for strength testing. Coring shall commence within 5 days of notification by the Engineer. Drilled cores shall be obtained by the Contractor in the presence of the Engineer and tested at the Contractor's expense in accordance with ASTM C 42 by a laboratory acceptable to the Engineer. Drilled cores having a minimum nominal diameter of 4 inches shall be obtained unless otherwise directed by the Engineer. A minimum of three cores shall be taken in each area represented by the failing 28-day compressive strength tests. Unless otherwise directed by the Engineer, the cores shall be tested wet following a 40-hour submergence. If each core produces compressive strength test results 85 percent or greater than the specified 28-day compressive strength, the concrete represented may be accepted with no further action required.

201-1.2.1 Portland Cement. All cement to be used or furnished shall be Type II low alkali portland cement conforming to ASTM C 150, or Type IP (MS) portland-pozzolan cement conforming to ASTM C 595, unless otherwise specified. Either cement shall conform to the low alkali requirements of Table IA of ASTM C 150. Type IP (MS) cement shall contain no more than 20 percent pozzolan, which shall be inter-ground with clinker.

The Contractor shall furnish a Certificate of Compliance signed by the manufacturer identifying the cement and confirming compliance. Supporting test data will be furnished upon request by the Engineer.

Whenever suitable facilities are available for handling and weighing bulk cement, they shall be used. Otherwise, cement shall be delivered in original unopened sacks that have been filled by the manufacturer and are marked with his name or brand, type, and weight.

Cement shall be stored in such a manner as to permit ready access for inspection and sampling and suitably protected against contamination and moisture. Should any cement show evidence of contamination or be otherwise unsuitable, the Engineer may reject it and require that it be removed from the site.

All portland cement used in concrete for any individual structure shall be of the same brand and type unless otherwise approved by the Engineer.

201-1.2.2. Aggregates. Aggregates shall conform to the requirements prescribed in 200-1 and shall be approved by the Engineer prior to use. Aggregate shall be of such character that it will be possible to produce workable concrete within the limits of slump and water content in 201-1.1.2 and 201-1.3.3.

Methods of handling materials resulting in segregation, degradation, or the combining of materials which results in failure to meet specifications shall not be permitted. The free moisture content of sand shall not exceed 8 percent at the time of batching.

Aggregates shall be nonreactive when tested in accordance with ASTM C 289 and evaluated in accordance with Appendix A-1 of ASTM C 33. Aggregates found to be potentially reactive may be used only upon written approval of the Engineer.

201-1.2.3 Water. Water used for concrete shall not contain deleterious substances. Water shall not contain an amount of impurities that will cause a change in the time of setting of portland cement of more than 25 percent nor a reduction in relative mortar strength at 7 and 28 days of more than 10 percent compared to results obtained with distilled water.

In conventionally reinforced concrete work, water shall not contain more than 1,000 ppm of chlorides calculated as Cl, nor more than 1,000 ppm of sulfates calculated as SO₄.

In prestressed concrete work, water shall not contain more than 650 ppm of chlorides calculated as Cl, nor more than 800 ppm of sulfates calculated as S0₄.

In nonreinforced concrete work, water shall not contain more than 2,000 ppm of chlorides calculated as Cl, nor more than 1,500 ppm of sulfates calculated as SO₄.

201-1.3.1 General. Aggregates and cement shall be proportioned by weight except that when the amount of concrete required for any one contract is 10 cubic yards or less, the materials may be measured by volume. Materials that are proportioned by volume shall be measured in containers of known capacity.

Weigh hoppers shall be charged from bins located directly over them or from conveyor belts. When conveyor belts are used, there shall be a separate belt for each size aggregate. There shall be a moisture meter installed, accurate within I percent of actual moisture content, to indicate moisture in the sand.

Bulk cement shall be weighed in an individual hopper and kept separate from the aggregates until ingredients are released for discharge. The cement hopper shall be attached to a separate scale for individual weighing.

The amount of water added to the mixture shall be measured into the mixing drum through a valve with a positive cutoff. When water is measured by weight, it shall be weighed on a separate scale.

Whenever a portable batch plant is set up at a new location the scale assemblies shall be inspected and certified regardless of the date the scales were last tested.

Scales utilized in proportioning shall be either spring-less dial, multiple beam, or solid-state digital strain gage transducer. Scale graduation shall be no greater than the following:

Aggregate Scales 25 Lbs.

Cement Scales 5 Lbs.

Water Scales 5 Lbs.

If a multiple beam type scale is used, the scale shall be provided with an indicator operated by the main beam which will give positive visible evidence of over or under weight. The indicator shall be so designed that it will operate during the addition of the last 400 pounds of any weighing. The overtravel of the indicator hand shall be at least one-third of the loading travel. Indicators shall be enclosed against moisture and dust.

Weighing equipment shall be insulated against vibration and movement of other operating equipment in the plant. When the entire plant is running, the scale reading at cutoff shall not vary from the weight designated by more than 1 percent for cement, 1 percent for water, 1-1/2 per-cent for any size of aggregate, nor 1 percent for the total aggregate in any batch.

201-1.3.2 Combined Aggregate Gradings. If the combined aggregate grading conforms to the grading of its designated class, the individual grading required by 200-1.4 and 200-1.5 may be waived. The combined aggregates shall conform to the gradings specified in the following table:

201-1.3.3 Concrete Consistency. The amount of water added at the mixer shall be regulated to take into account the free water in aggregates. Free water is defined as the total water minus the water absorbed by the aggregate in a saturated surface-dry condition.

The amount of water used in the mixture shall not exceed the amount necessary to permit practical placement and consolidation of the concrete. Total free water in the mixture shall not exceed an amount producing the maximum slump specified in 201-1.1.2, and shall not exceed amounts shown in the following:

1. When the coarse aggregate is composed solely of crushed rock, the above values may be increased up to 20 pounds of water per cubic yard.

201-1.4.1 General. Machine mixing will be required in all cases other than those in which it would obviously prove to be impractical, in which case hand mixing is permitted. Mixing shall be commenced as soon as possible after the cement is placed in contact with the aggregates, but in no event shall the intervening period exceed 30 minutes.

All concrete mixers shall be of such design and construction and so operated to provide a properly mixed concrete with uniform distribution of ingredients. Mixers shall be maintained properly and be in working order and not have any aluminum parts which will have direct contact with concrete.

201-1.4.2 Paving and Stationary Mixers. Paving and stationary mixers shall be equipped with an accurate automatic timing device so designed and constructed as to lock the discharge lever. The regulation setting of this device shall be under the supervision of the Engineer. Water control equipment shall also be provided with each concrete mixer.

The proper proportions of aggregate, cement, and water for each batch of concrete shall be placed in the mixer and mixed for a period of not less than I minute (1-1/2 minutes for reinforced concrete).

The rotating speed at which the mixer shall be operated shall conform to that recommended by manufacturer. The total volume of materials in any one batch shall exceed neither the water level capacity of the mixer nor the manufacturer's guaranteed capacity of the mixer.

201-1.4.3 Transit Mixers. The type, capacity, and manner of operation of the mixing and transporting equipment for ready-mix concrete shall conform to the current "Standards for Operation of Truck Mixers and Agitators of the National Ready-Mixed Concrete Association" and the 'Truck Mixer and Agitator Standards of the Truck Mixer Manufacturers Bureau". Transit mix concrete trucks shall be equipped with an automatic device for recording the number of revolutions of the drum during the mixing period. Each mixer and agitator shall have attached thereto in a prominent place, a metal plate or plates, installed by manufacturer on which is plainly marked the capacity of the drum in terms of the volume of mixed concrete and the speed of rotation for the agitating and mixing speeds of the mixing drum or blades.

Each mixer shall have an identification number painted on it that can be easily read from the batching platform.

The total volume of materials introduced into the mixer shall not exceed the manufacturer's guaranteed mixing capacity. If the concrete so mixed does not meet the uniformity requirements, the amount of materials charged into the mixer shall be reduced.

The drum of the mixer shall be completely emptied of any previously mixed load. The proper proportions of aggregate, cement, and water for each load of concrete shall be placed in the mixer and shall be mixed between 70 and 100 revolutions at the designated mixing speed. Additional revolutions of the drum shall be at designated agitating speed. The revolving of the drum shall be continuous until the concrete is completely emptied from the drum.

When concrete is being placed for pavement or concrete structures, all wash water shall be emptied from the mixer before any portion of the succeeding load is placed. For all other work, the mixer shall be empty or may carry 10 gallons of water in the drum. Adequate control of ready-mixed concrete requires additional added water mixed into the batch at discharge point. This water shall be mixed for a minimum of 30 revolutions at rated mixing speed. Water shall not be added to the load during transit.

The total elapsed time between addition of water at the batch plant and discharging the complete mix shall not exceed 90 minutes. Under conditions contributing to quick setting, the Engineer may reduce this time.

The Engineer shall be provided with a legible certified weighmaster certificate. When mix proportions have been designated for a project and are identified by number the Engineer may accept a legible certified weighmaster certificate which shall contain the following information:

When the mix proportions are not designated by number, or when required by the Engineer, the certificate shall contain the following additional information:

Space shall be provided on the certificate so that the amount of water added on the job may be indicated.

201-1.4.4 Hand Mixing. Hand mixing is permitted when the amount of concrete required is less than 1 cubic yard. Hand-mixed concrete shall be mixed on a watertight platform or in a mortar box in batches not to exceed 1/3 cubic yard each. The aggregates shall be spread in a uniform layer over which the required quantity of cement shall be evenly distributed. The entire batch shall be turned with shovels until the ingredients are throughly blended before adding water. After adding the proper amount of water, the batch shall again be turned with shovels until a uniform consistency is obtained. Methods of hand mixing which allow the loss of mixing water will not be permitted.

201-1.5 Transporting Batched Materials and Mixed Concrete. The compartments of trucks or other equipment used for the purpose of transporting proportioned dry aggregate and cement, or mixed concrete, shall be suitably constructed to protect and prevent loss or leakage of con-tents during charging, transit, or discharging.

Note: At least two sample bars shall be taken from each bar size.

201-2.5.3 Wire Reinforcement. One sample consisting of two pieces, each 3 feet long, shall be taken from each 2-ton lot or less of each size of wire delivered to the job site,

201-2.5.4 Wire Mesh Reinforcement. Two samples of a size suitable for testing shall be taken from each 3,000 square feet of fabric or fraction thereof.

1. Mixing ratio of material: Add 10 ±0.1g. of sodium fluosilicate powder to 200g. of emulsion component.

2. Mixing ratio of material: Add 12mL of setting agent component to 8 fluid ounces of emulsion component.

201-3.8 Type "E" Joint Sealant (Polysulfide Polymer and Rubber Rod). Polysulfide polymer type joint sealant shall be a two-component, plastic, rubber like, cold-applied joint sealant. This material shall resist the intrusion of foreign materials into the joint throughout repeated cycles of expansion and contraction.

The joint sealant shall be packaged in sealed containers identified by the name of the manufacturer, lot number, and date, and bear instructions for mixing and application. Accelerator containers shall be marked "A", and polysulfide containers shall be marked "B". The weight of component "A" in the mixture shall not less than 10 percent of component "B". Minimum polysulfide content of the mixture shall be 20 percent by weight.

Upon opening the container, component "B" shall not exhibit more than a slight degree of "skinning" on the surface of the material.

The joint sealant shall comply with the following requirements when laboratory mixed materials are tested in accordance with Calif. Test 413:

The following tests are to be performed on the mixed material after 96 hours of aging at 77 F:

The following test is to be performed on the sample from the resilience test above, oven-aged for 7 days at 158°F:

1. This requirement applied if the penetration at 77°F, after 96 hours aging at 77°F, is 100 to 120.

The rubber rod shall be a cellular synthetic rubber, either butyl or neoprene, of circular cross section with continuous skin impervious to water. It must comply with the following requirements:

201-3.9 Test Report and Certification. When requested by Engineer, the Contractor shall provide at delivery time, certified copies of the vendor's test report. This shall indicate the vendor name, type of joint sealant, date and point of delivery, quantity, ticket number, lot number, and results of the required test. The test report shall be signed by an authorized representative of the vendor. The certified test reports and testing required in connection therewith shall be without cost to the Agency.

201-5.2 Cement. Cement shall conform to 201-1.2.1.

201-5.3 Sand. Sand shall conform to requirements of 200-1.5.3. In proportioning the sand it shall be measured loose (without shaking or compacting) in measuring boxes or other suitable containers of known capacity.

201-5.4 Water. Water shall conform to 201-1.2.3.

201-5.5 Admixtures. No admixture shall be used in mortar unless approved by the Engineer.

201-5.6 Quick-Setting Grout. Quick-setting grout shall be a high strength nonstaining grout approved by the Engineer. It shall reach an initial set within 90 minutes at 70°F and reach minimum compressive strength of 25 00 psi within 24 hours. Shrinkage shall be less than 0.1 percent when tested, using the test procedures of ASTM C 596. The grout shall be mixed, handled and placed in accordance with manufacturer's instructions.