Laserfiche WebLink
fednesday, Iarch 2nd.. , 1927. <br />2 ?'v <br />Asphaltic Concrete--- Light Traffic. <br />5 inch base <br />I inch binder course <br />I inch wearing surface <br />In all other resppets this type to meet the requirements of <br />the specifications for "Asphaltic Concrete- Heavy traffic." pavement. <br />CONCRETE PAVE21M * HEAVY TRAFFIC <br />Same specifications as in use last year; viz, eight (811) <br />inch slab v,,ith fifty (50) puunds of reinforcement per hundred (I00) square feet. <br />CONCRETE PAVEUENT **.LIGHT TRAFFIC <br />Seven (711) inch slab with no steel reenforcement. Inall <br />Other respects this type to meet the specifications for "Concrete Pavement -Heavy <br />Traffic." <br />Concrete Foundations for fa.vements. <br />Thickness to be as specified for light and heavy traffic types, <br />Apportionment of materials in the concrete to remain the sane <br />as now specified; viz, I: 3: 6. <br />Fine and Course Aggregates to be measured separately; the <br />course aggregate to be washed gravel; the fine aggregate to be clean, sharp sand. <br />Both sand and gravel to meet the requirements of specifications for "Fine and <br />Course Aggregates"herein. <br />Bank run material to be eliminated from the specifications. <br />CONCRETE CURB. <br />Dimensions and apprrtionment of materials to remain substantial) <br />the same as no?,; specified. <br />Steel forms. recommended but not required. <br />I <br />Entire curb to be constructed of the same mix instead of two <br />separate mixtures as novr specified. <br />The fine and course aggregates to be the same as recommended <br />above for "Concrete Foundations." <br />Bank run materials to be eliminated from specifications. <br />C ,, ; ENT VVALH. <br />This specification has been modernized to make it applicable <br />to rresent day needs. I would recommend that the two course construction be <br />i continued; viz, three and one-quarter(3111) inch wearing surface. <br />I <br />Expansion joints to be constructed at each twenty five (2511) <br />feet. <br />The fine and course aggregates to meet the requirements of the <br />specifications for'"ine-and course Aggregates" as recommended above in "Concrete <br />Foundations for Pavements". <br />Apportionmend of materials to be of the ratio I: 2: 4/ <br />I <br />Ban., run material to be eliminted from specifications. <br />The use of steel forms is recommended but not required in <br />1� this speci:Pication. <br />The major change: recommended above in any one or all of the <br />specifications has been eliminatinn of the use of bank run material in concrete. <br />I feel that the use of this material last_yearizas responsible in a great measure <br />for more defects in our work than any one other cause. Bank run material is <br />never uniform and cannot be kept free from foreiggn substances which are injurious <br />to concrete. This was evident last .year on several important projects where coal, <br />I <br />wood and clay were picked out of * completed curb and walk work. This condition <br />was just as true in pavement foundations but, of course, harder to detect. Some <br />of the material used last year, such as referred to above, should have been <br />rejected but this was not possible with the efficiency of our inspection at that <br />date. <br />The safest and most satisfactory way to handle this situation <br />is to have fine and course aggregates measured separately. The best authorities, <br />I am sure, will support this view. To my knowledge, there are no cities theize I <br />k <br />of South Bend that permit the indiscriminate use of banrun materials in their j <br />0 <br />