B09_CHOH_245002_287711_Amd_3_-_041000_Mortar_Update_0004.pdf

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MORTAR

CHOH 245002 & 287711

SECTION 04 10 00 – MORTAR

PART 1 - GENERAL

1.1 DESCRIPTION

A. The work of this section consists of furnishing mortar for both repointing and for masonry work specified in other sections.

B. There are two types of mortar to be provided: "Natural Cement" and "Portland Cement".

C. In the following locations, provide the type of mortar listed below:

1. Lock #1 - Natural Cement

2. Lock #2 - Natural Cement

3. Level #1 Wall North - Portland Cement

4. Level #1 South - Natural Cement

5. Level #2 Wall - Natural Cement

6. Wisconsin Ave North - Portland Cement

7. Wisconsin Ave South - Portland Cement

8. Grace Street - Portland Cement

9. 1046 Potomac Street - Portland Cement

10. 34th Street - Portland Cement

11. Lock #5 - Natural Cement

12. Lock #5 Retaining Wall - Natural Cement

13. Inlet Lock - Portland Cement

14. Guard Lock - Portland Cement

D. The mortar shall match as close as possible, the color, texture, and tooling of the existing mortar found at each of the fourteen locations.

1.2 RELATED WORK

A. Repointing of Existing Stone Masonry – Section 040305.

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B. Stone Masonry - Section 040307.

1.3 SUBMITTALS

A. As specified in Submittals - Section 013323.

B. Mortar Samples:

1. At each of the fourteen locations, submit three samples approximately 0.5 inches x 6 inches for approval of color by the CO. Samples shall have cured for 28 days. Each mortar sample shall use sand from a different local source. Color pigment shall not be used. Submit mix proportions and ingredients with each mix. Include the proposed mortar profile to be used at each location. For each location and for each of the three samples, one set of three mortar cubes shall be cast and tested for compressive strength at 7 and 28 days. (ASTM C109M).

Submit test reports for Mortar Cubes along with the samples.

C. Certificate: Manufacturers’ cut sheets and certifications that materials and products meet specified requirements where specified.

D. Mortar test results related to Field Quality Control.

1.4 PRODUCT HANDLING

A. Delivery: Deliver materials in manufacturers’ original, unopened, protective packaging.

B. Storage: Store cementitious materials in a dry area, under cover and off the ground.

1.5 PROJECT CONDITIONS

A. Do not place mortar when temperature is below 40 degrees F unless the CO has approved a written plan detailing means that will be provided to heat sand or water and ensure that mortar will harden without freezing.

PART 2 - PRODUCTS

2.1 MORTAR MATERIALS

A. Natural Cement Mortar Mix Design: Proportions shall be 1 part natural Cement to 2 parts sand.

Target design strength is minimum 800 psi at 56 days.

1. The Natural Cement mortar shall include the following components:

a. Natural Cement: Natural cement or quick-setting natural cement processed from argillaceous limestone and meeting the requirements of ASTM C10. Artificial mixtures of other cementitious materials, fly ash, slag, Portland cement, hydraulic lime or lime-pozzolan mixtures are not permitted as substitutes for natural cement.

b. Hydrated Lime: ASTM C207 Type S, incorporated as a finely divided powder in uniform particle size, free of lumps, flakes or other inconsistencies.

c. Mortar Aggregate: ASTM C144 natural sand blend, rounded to sub-angular in shape, washed, screened and dried. Aggregate to be selected to match the color and texture

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of the original mortar aggregates as closely as possible while remaining in compliance with ASTM C144 grading and soundness requirements.

d. Admixtures: Time of setting can be prolonged with the addition of an approved set retarding admixture. No other admixtures shall be used without the express written consent of the Government. Calcium chloride is not permitted in any mortar.

e. Water: Potable, free of deleterious quantities of materials which may affect mortar performance or appearance.

B. Portland Cement Mortar Mix Design: Proportions shall meet ASTM C270 requirements for type N mortar. Target design strength is 1200 psi at 28 days.

1. The Portland Cement mortar shall include the following:

a. Portland Cement: ASTM C150-00, Type II, white, non-staining, 0.6 percent max Alkali.

b. Hydrated lime: ASTM C207 Type SA.

c. Mortar Aggregate: ASTM C144 natural sand blend, rounded to sub-angular in shape, washed, screened and dried. Aggregate to be selected to match the color and texture of the original mortar aggregates as closely as possible while remaining in compliance with ASTM C144 grading and soundness requirements.

d. Water: Potable, free of deleterious quantities of materials which may affect mortar performance or appearance.

PART 3 - EXECUTION

3.1 MIXING MORTAR

A. Mixing process shall follow the recommendations in ACI 531. Do not use admixtures unless otherwise indicated.

B. Thoroughly mix cementitious aggregate materials together before adding water. Then mix again, adding only enough water to produce a damp, unworkable mix that will retain its form when pressed into a ball. Maintain mortar in this dampened condition. Add remaining water in small portions until mortar reaches desired consistency. Use mortar within 30 minutes of final mixed.

Do not retemper or use partially hardened material.

3.2 FIELD QUALITY CONTROL

A. The Contractor’s testing agency shall prepare a set of specimens for testing according to ASTM 780 Annex A4 for mortar aggregate ration and for Annex A6 compression strength tests for every day’s work. The Contractor shall be responsible for having the compression tests done and for providing the test results to the CO within 10 days of the test. Provide compression tests at 7 days and at 28 days for Portland Cement Mortar and 56 days for Natural Cement Mortar.

B. These results will be used to evaluate uniformity of mortar production, they are not required to meet the minimum compressive strength. If test results vary more than 30% from the

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preconstruction testing values, the cause(s) of that variance shall be established and reported to the CO. Any necessary corrective action shall be proposed to the CO and once approved, shall be taken.

C. The Contractor’s testing agency shall provide inspection of proportions used for mixing mortar and batching procedures used at least once for each day’s work.

END OF SECTION 04 10 00