10-40 Section 1006. Patching, Repair, and Overlay Mixtures
1006.01 Description
This work consists of mortar and concrete mixtures for patching, repair, and concrete overlays in accordance with section 1001 and section 1004, except as modified by this section.
1006.02 Materials
Provide the materials in accordance with the following: Portland cement, Ty pe I, Type IA .......................................................... 901 Silica Fume ........................................................................................... 901 Coarse Aggregate 6AA, 6A, 26A ........................................................... 902 Fine Aggregate 2NS ............................................................................. 902 Polypropylene Fibers ............................................................................ 903 Concrete Admixture .............................................................................. 903 Water ..................................................................................................... 911
A.General Requirements. Provide air -entrained concrete or mortar unless otherwise required by the contract. Produce mixtures meeting the requirements specified in Table 1006-1, Table 1006-2, and Table 1006 -03. Do not use slag aggregates.
B.Mortar and Concrete Patching Mixtures: Types F -L, M, C -L, C -L-HE, C, and C -HE. Provide mortar and concrete patching mixtures for patching bridge decks or substructure elements. Select a mixture from Table 1006- 1 based on the depth of patched area and the length of curing time available before allowing traffic on patches . Provide either regular strength or high- early strength patching mixtures .
C.Latex Modified Concrete (LMC) Overlay Mixture. Provide 100% crushed 26A coarse aggregate. Ensure that LMC meets the strength requirements of Grade 4500 concrete as specified in Table 1004-1.
D.Silica Fume Modified Concrete (SFMC) Overlay Mixture . Provide 100% crushed 26A coarse aggregate. Ensure that SFMC meets the strength requirements of Grade 4500 concrete as specified in Table 1004-1 . Supply the silica fume admixture in dry -densified form . Remove dry -densified silica fum e from packaging. Do not incorporate the packaging into the concrete mix. MDOT Standard Specifications for Construction Section 1006 10-41 E. Grade P -NC Pavement Repair Mixture . Submit a JMF for Grade P -NC pavement repair mixture to the Engineer for approval per subsection
1003.03 C.2.
1006.03 Construction
A.Equipment for LMC . Provi de equipment for producing LMC by volumetric batching and continuous mixing in accordance with ASTM C685/C685M . Provide certification to the Engineer, or demonstrate by field tests, that equipment is calibrated for yield and proportioning. Obtain the Engin eer’s approval for equipment before starting production. Supply handheld vibrating equipment to consol idate the repair concrete.
B.Mixing Concrete and Mortar for Structural Patches and Overlays. Proportion and mix latex modified mixtures in self -contained mobile continuous type mixers in accordance with ASTM C685/C685M, except that the Engineer will determine requirements for certification. Mix and transport SFMC and mortar patching mixtures as specified in subsection 1001.03. Do not deliver more than 7.0 cubic yards of SFMC per load to the bridge site in ready -mix trucks. Ensure that silica fume modified mixtures receive at least 100 revolutions at mixing speed after adding dry -densified silica fume . Add additional high-range water reducer (HRWR) to the mixture at the project to adjust the slump to the required range. After adding the HRWR, provide at least 60 revolutions at mixing speed. Do not add water at the project. Allow a cure time of at least 5 days for regular strength patching mixtures and at least 24 hours for high- early strength patching mixtures . Keep patches with regular strength LMC continuously damp for the first 24 hours . Remove the curing material at the end of the 48-hour wet cure period and allow concrete to air cure for an additional 48 hours . Maintain patches with high-early strength LMC continuously damp for at least 24 hours.
C.Mixing Grade P -NC Pavement Repair Mixture . Produce Grade P -NC pavement repair mixture according to subsection 1001.03.
1006.04 Measurement and Payment
The cost of mortar and concrete patching, repair, and resurfacing mixtures is included in the unit prices for other relevant pay items. 10-42 Table 1006- 1: Structure Patching Mixtures Depth of Patch (inch) Aggregate Required(a),(b) Mixture Type(c) Mixture Proportions per cyd, dry weight Air Content Cement (lb) Net Water (approx.) (lb)(d) Latex Admixture (lb (gal) ) Fine Aggregate (lb) Coarse Aggregate (lb) <1.5 2NS F-L 752(e) (f) 235 (28.0) 2450 N/A 6.0 ±2.0% 1.5–4 2NS and 26A M 799 358(g) N/A 1260 1260 7.5 ±1.5% ≥1.5 2NS and 26A C-L C-L-HE 658(e) 846(e) 169(f)
f.143 (17.0 ) 228 (27.0 ) 1348(i) 1308(i) 1458(i) 1416(i) 4.5 ±1.5% 4.5 ±1.5% >4(h) 2NS and 6AA C C-HE 705 846 315(g) 300(g) N/A N/A 1220 1220 1530 1590 6.5 ±1.5% 5.5 ±1.5%
a.Ensure that the coarse aggregate’ s absorption does not exceed 2.5% in accordance with ASTM C127.
b.Aggregate weights specified in the table are based on a dry bulk specific gravity of 2.65 for gravel and stone. Adjust the weights if t he specific gravity of the materials used varies by more than 0.02 from the specified values.
c.C = coarse; F = fine; HE = high-early strength ; L= latex modified; M = medium . Type F mixtures are mortars.
d.The specified quantity of water is approximate. Use the least amount of water to provide the consistency required for the spe cific mixture.
e.Use only Type I portland cement i n these mixtures.
f.Add water, in addition to water in the latex admixture, to control slump to within 3 to 5 inches . Measure slump from 4 to 5 minutes after discharge from the mixer. During th e waiting period, deposit concrete on the deck and do not disturb. If placing mixtures on sections within super -elevated curves, the Contractor may need to use the lower allowable range of the slump requirement, as determined by the Engineer. Do not exceed water -cement ratio, by weight, of 0.30 including water contained in the latex emulsion.
g.Control water to provide a stiff, workable mixture with a 1 - to 2-inch slump. During hot and windy weather, the Contractor may increase the slump to 3 to 4 in ches , as determined by the Engineer.
h.Substructure repairs.
i.The aggregate proportions are approximate; due to gradation changes, the Engineer may adjust. The Contractor may increase the fine aggregate quantity by no greater than 5% by weight of total aggregate if reducing coarse aggregate by an equivalent volume. MDOT Standard Specifications for Construction Section 1006 10-43 Table 1006- 2: Overlay Mixtures Mixture Type Aggregate Slump (inch) Air Content Admixture Required Mixture Proportions lb/yd³, dry weight Cement(a) Dry Densified Silica Fume(b) Net Mix Water Fine Agg Coarse Agg Latex Admixture SFMC 2NS and 26A(c) 4–6 6.5 ±1.5% (d),(e),(f) 618 40 273(g) 1273 1601 — LMC 2NS and 26A(c) (h) 4.5 ±1.5% — 658 — (h) 1490(i) 1300(i) 206
a.Use only Type I portland cement.
b.Aggregate weights specified in the table are based on a dry bulk specific gravity of 2.65 for gravel and stone. Adjust the weights if the speci fic gravity of the materials used varies by more than 0.02 from the specified values.
c.Provide coarse aggregate, 95% minimum cru shed materials in accordance with Michigan Test Method ( MTM) 117, with an absorption no greater than 2.5%, in accordance with ASTM C127.
d.Water -reducing high -range admixture or water -reducing high-range and retarding admixture.
e.Virgin polypropylene collated fibers at 2 lb/yd³.
f.Air-entraining admixture.
g.Provide a net water to cementitious material ratio of 0.41 (cementitious material includes cement and silica fume). Add water in addition to water in the latex admixture to control slump to wit hin 3 to 5 in ches . Measure slump from 4 to 5 min utes after discharge from the mixer. During the waiting period, deposit concrete on the deck and do not disturb. If placing mixtures on sections within superelevated curves, the Con tractor may need to use the lower allowable range of the slump requirement, as determined by the Engineer. Do not exceed water -cement ratio, by weight, of 0.30 including water contained in the latex emulsion.
h.Aggregate proportions are approximate; due to gradation changes, the C ontractor may increase proportions by no greater than 5% by weight of total aggregate if reducing coarse aggregate by an equivalent volume.
i.For SFMC mixtures, the Contractor may use a blended silica fume portland cement. However, if the silica fume con tent of the blended material is greater than 8% of the total cementitious material, submit to the Engineer modified mix proportions with Type I portland ceme nt added to the blended material to achieve the equivalent individual cementitious material mixture proportions. MDOT Standard Specifications for Construction Section 1006 10-44 Table 1006- 3: Pavement Repair Mixture Concrete Grade Maximum Cementitious Content (lb/cyd) Air Content Coarse Aggregate Slump (inch) Minimum Flexural Strength (psi) 28-day Compressive Strength (psi) Section References P-NC 658(a),(b) 5.5–8.5% 6AA(c) 0–6 300(d) 3500(e) 603, 801
a.The Engineer may permit a maximum cementitious content of 752 lb/cyd when the weather is forecast to be below 50°F, at no additional cost to the Engineer.
b.Type III cement is not permitted.
c.The Contractor may use an optimized aggregate gradation.
d.Use flexural strength for opening to traffic.
e.The Engineer wil l not require 28 -day compressive strength test cylinders for concrete pavement repair.
Source: Michigan Standard Specifications for Construction, 2020 Edition. Pages 1078–1082 of 1,146.