Category:1019 Cement: Difference between revisions

This guidance establishes procedures for inspecting, sampling, and accepting cement at the source and destination and to establish a list of qualified cement sources.

1019.1 Apparatus

Keep all sample containers and equipment used in sampling cement clean and free of moisture or any foreign material. It is important that the sample be kept in airtight, moisture-proof containers from the time it is obtained until tests are started. The apparatus consists of:

(a) Canvas bags with plastic liners.

(b) Rubber bands for securely fastening the top of plastic liners.

(c) Slotted tube, tube sampler, scoop or any other device suitable for obtaining the sample.

(d) Labeling materials.

1019.2 Procedure

1019.2.1 Source Acceptance and Qualification

All cement for use in MoDOT projects must be furnished from a qualified manufacturer or terminal and must comply with the requirements of Sec 1019. The procedures for qualification are listed in Sec 1019. Direct questions from potential suppliers concerning qualification to the Central Office. The latest copy of each manufacturer's quality control plan is to be kept on file in the Central Office. Send any updates to the quality control plan direct to the Chemical Laboratory Director.

With approval of the State Construction and Materials Engineer, small quantities of specialty cement may be sampled and inspected at destination. This approval will be granted infrequently and only under circumstances where it is difficult or impractical to comply with the acceptance procedures in Specification Sec 1019.

1019.2.2 Inspection and Sampling

The Senior Cement Chemist may coordinate with the manufacturer to obtain a semi-annual split sample for each approved cement plant. Complete a sample record in AASHTOWARE (AWP) showing manufacturer, silo number, type and other pertinent information. Designate sample type as a "Split Sample". The manufacturer shall furnish the manufacturer’s test results to the Senior Cement Chemist within two weeks after completion.

1019.2.3 Disqualified Facilities

Manufacturers that fail to comply with the qualified status as set forth in Sec 1019 will be required to designate the silo(s), bin(s), or storage facility from which they propose to furnish cement for MoDOT projects. The producer must sample, test, and report satisfactory test results for each designated silo, bin, or storage facility. Prior to any shipment and following a satisfactory report furnished to the Chemical Laboratory Director, each silo, bin, or storage facility will be sampled and sealed by the Senior Cement Chemist. If the results of testing by the Central Laboratory are satisfactory, the sealed silo, bin, or storage facility will be approved. This procedure will continue until adequate quality control has been re-established.

1019.2.4 Destination Inspection of Approved or Company Certified Cement

The ready-mix, precast, or paving plant operators shall furnish a copy of the bill of lading or delivery receipt for each shipment to MoDOT work.

Use the following procedure to sample cement on paving jobs and at ready-mix plants. Samples shall weigh a minimum of 5 lb (2.5 kg). Obtain the samples from the storage bin or weigh hopper just prior to incorporation into the mix to represent the material being used. Truck samples are not normally acceptable for destination sampling.

Take a sample at the rate of one per 9,000 cubic yards (6,900 cubic meters) of concrete produced for each paving plant with a maximum number of one per day and promptly submit to the Central Laboratory.

At ready-mix or precast plants, take a sample at the rate of one per 9,000 cubic yards (6,900 cubic meters) of concrete produced for Missouri Department of Transportation work, or as directed by MoDOT, with a minimum of one sample every other month, during the period that the ready-mix or precast plant is furnishing concrete for Department work. If a ready-mix or precast plant is using more than one type or source of cement for Department work, the samples should be taken alternately to cover the different types or sources.

Place samples taken at destination in a canvas bag containing a plastic liner and ship to the Central Laboratory. Complete a sample record in AWP showing the manufacturer, type, and other pertinent information such as contractor, plant location, and county. The sample type shall be designated as a "Proj - Check Sample". “Proj – Check Sample” is to be selected even for precast work when the items made are for stock.

1019.2.5 Destination Inspection of Small Limited Quantities of Cement

When destination inspection of small limited quantities of cement is permitted, the inspector shall sample the cement, as applicable for bulk or packaged cement. The cement offered for inspection shall not be used until tested and approved by the Laboratory. Cement showing any appreciable amount of caking or storage hardening shall not be sampled or used. The sample shall be shipped to the Central Laboratory in a canvas bag containing a plastic liner. Complete a sample record in AWP showing the manufacturer and other pertinent information such as source, contractor, project or precast plant, and intended use.

The district is to ensure that the qualified manufacturer is certifying each shipment in accordance with Specification Sec 1019, including all requirements for signatures and shipments from other entities.

Where test reports are necessary in the District as a basis of acceptance or rejection of small limited quantities, place a note in the remarks of the sample report similar to the following: "Small limited quantity of cement - please furnish test report."

1019.3 Sampling

Sample cement by the methods specified herein. A sample shall weigh a minimum of 5 pounds (2.5 kg). Samples obtained in one operation and representing a brief period in the cement stream shall be termed a "grab sample". Samples obtained by means of an automatic device that continuously samples a cement stream for either a short or extended period shall be termed a "continuous sample".

Samples may be taken from a conveyor delivering cement to bulk storage by either the grab or continuous method.

Samples may be taken from bulk storage at points of discharge by either the grab or continuous method. If a high circular silo is being sampled, all samples may be taken from one opening. When low rectangular bins are being sampled, the number of discharge openings employed in sampling shall be so that for no opening shall the number of samples represent more than one half the contents of the bin. Sampling from a discharge opening shall cease when any materials which have been placed on top of the cement in the bin or silo pass through the sampling opening.

Samples taken from bulk storage, bulk shipment of railway car, truck, or other transportation unit should be by the grab method. A sample taken from bulk storage shall be taken from at least three well-distributed points. A sample taken from bulk shipment may be obtained from one point in the car, truck or other transportation unit, including the top. Sampling device may be a tube sampler, scoop or any other device suitable for obtaining the sample.

Take samples from packaged cement by the grab method using a tube sampler. A sample taken from packaged cement shall be taken from at least three bags.

1019.4 Sample Record

Report of Laboratory test results on random samples of cement originating from a qualified manufacturer will not be distributed unless specifically requested and conditions warrant this information for a specific purpose. Laboratory test results on small limited quantities of cement will be reported and distributed as shown in Laboratory Testing for Sec 1019.

The receiving district Construction and Materials Engineer shall continuously monitor shipments to the particular ready-mix or paving plants to assure that sufficient inspected and certified cement is being shipped from an approved source.

Perform a review of each plant's inspector's daily report data at regular intervals not to exceed one week. Verify that enough tickets are shown to account for the amount of cement used and that the supplier and type are shown on the list of qualified sources. If the report does not contain the required information, notify the district Construction and Materials Engineer.

1019.5 Laboratory Testing for Sec 1019

1019.5.1 Sample Preparation

Prior to testing, a sample should be thoroughly mixed, passed through a No. 20 (0.850 mm) sieve, and brought to room temperature. All foreign matter and lumps that do not pulverize easily in the fingers must be discarded.

1019.5.2 Procedure

Chemical analysis is to be conducted according to ASTM C114 and MoDOT Test Method T46. In case of question, the referee methods of ASTM C114 are to be used. Original test data and calculations are to be recorded in Laboratory workbooks. Test results are then recorded through AWP and retained on file in the Laboratory.

Physical tests shall be conducted in accordance with the following methods:

(a) Fineness, Turbidimeter - ASTM C115

(b) Fineness, air permeability - ASTM C204

(c) Autoclave - ASTM C151

(d) Time of setting, Gilmore Needles - ASTM C266

(e) Time of setting, Vicat - ASTM C191

(f) Air content of mortar - ASTM C185

(g) Normal consistency - ASTM C187

(h) Compressive strength - ASTM C109

(i) False set - ASTM C451

Original test data and calculations are to be recorded in Laboratory workbooks. Test results are then to be recorded in AWP.

1019.5.3 Plant Inspection

Qualified cement producers and terminals shipping material by certification to Department projects shall be inspected on a regular basis by a representative of the Laboratory. This inspection shall include a review of plant facilities for producing a quality product, plant testing procedures, frequency of tests, plant records of daily test results and shipping information, company certification procedures of silos and/or shipments, and a discussion of items of mutual interest between the plant and the Department. The Laboratory representative shall coordinate test results and test procedures between the Laboratory and the respective plant laboratory, and investigate associated cement problems.

All silo certifications received in the Laboratory shall be checked for specification compliance and to determine if the required certifications have been furnished.

1019.5.4 Cement Processing Additions

Cement processing additions must be in compliance with AASHTO M 327 and M 85.

Notification prior to use is required and must be furnished in the following format:

a. Certification to be typewritten on the cement producer's letterhead.

b. Certification to be dated and submitted to: State Construction and Materials Engineer

c. Body of certification to state: "This is to certify that the cement processing addition __________, manufactured by __________ when added in the amount not exceeding _____ percent by weight for Type ____ cement, has been tested and found to comply with the requirements of AASHTO M 327 and M 85.

We further state that no other processing addition will be used unless a new certification is issued."

___________________

Cement Company

___________________

Company representative Signature

___________________

Title

Upon compliance of Laboratory tests and a review of the report as furnished, the manufacturer or sponsor will be notified by letter as to acceptability of the proposed product. If the product is prequalified for use, the letter shall contain a statement to the effect that "Department approval should not be construed to be an endorsement for and shall not be used for commercial promotion." Each prequalified brand and manufacturer of cement processing additions, along with the approved maximum addition rate, based on percent by weight of cement will be added to the list of "Qualified Brands and Manufacturers of Cement Processing Additions".

After prequalification of the cement processing addition is given to the manufacturer or sponsor and the cement company desiring to use that addition has complied with the procedure above, approval for use will be granted.

1019.5.5 Sample Record

The sample record shall be completed in AASHTOWARE Project (AWP) in accordance with AWP MA Sample Record, General, and shall indicate acceptance, qualified acceptance, or rejection. Appropriate remarks, as described in EPG 106.20 Reporting, are to be included in the remarks to clarify conditions of acceptance or rejection. Test results shall be reported on the appropriate templates under the Tests tab.