{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

ETC 1250 Lesson 02c - Lesson#2c ETCt250 Properties of...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Background image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Lesson #2c ETCt250 - Properties of Materials . Chapter #2 . Pg 45 - 67 Aggregate Properties - Compaction - Welt-graded aggregates compact more easily than poorly graded aggregates. - Aggregates at optimum moisture content (ornc) compact more easilythan aggregates at below or above optimum. 7 omc for wengraded bani-r gravel might be about 7% — omc for a sand clay might require about 13%. Vibratory g Tam ping foot ? - Compacted with: Sheepsfoot Pneumatic i Aggregate Properties Stabilizing Aggregate Stabilization can occur with the addition of a “binder" Binders: - A binder is a fine material used to fill the voids without separating the larger particles from contact with each other - The fine particles hold the coarser ones by preventing movement between them BrunsL Introduction Aggregate Properties Compaction Pavement Base Stabilizing Aggregate Permeability Aggregate Properties Pavement Base Top course and binder is asphalt (flexible) or concrete (rigid). Natural soil may be existing or fill Base Course below pavement and rural roads is for load bearing — Well graded and compacted — Yet sufiicient voids to prevent capitlary action Base Course below rigid is to protect the rigid course from detrimental effects of water — Frost heave — Standing water — Pumping (pg 51) Thus must be large aggregate with substantial voids to allow drainage and prevent capiliaryr action. Side-hm and" WM nlluri sour Nan-rel nil in} We" Mm: WM»! m! Ila emf” Comm normal wil Natural ”it lhl Rural mu CORN“ WW mural mil Nflul'll will {cl Form mm: may! W“ Aggregate Properties Stabilizing Aggregate Binding Agents: Clay is cohesive (or has the tendency to stick together} Salts — Calcium chloride and sodium chloride mixed with water forms a brine which has higher surface tension — Increased cohesion — Allows greater compaction Lime (Burned Limestone) — Reacts with Clay to produce larger better gradiated binder — Reacts with aggregate to solidify mass as a cementing agent which holds the particles together (cohesion) Portland cement and Bituminous cement 7 Binds with aggregate to form concrete holding the particles together (cohesion) Aggregate Properties Aggregate Properties Permeability . -. .. Permeability A filter works as shown - __ __.. -- - Filters to the left hold " .. soil in place, yet allow drainage. Typically mineral aggregates Each layer is held in place by larger particles and in turn holds back smaller particles Size and gradation are of . . Filters to right clean primary Importance for a filter impurities from water. Typically sand, coal, charcoal, and diatomaceous earth Tests - Size and Tests - Size and Gradation Gradati 0n - A standard selection Of seives is below: Seives are used to sort aggregates by size NOMINAL NOMINAL NOMINAL OPENING . OPENING . . OPENING iN. . IN. . N. A test seive is seen at the left '- 4.000 0151‘ 0.0025 5.500 0.132 0.0025 The seive number is the number of - 3,000 - 0.111 . 0.0021 holes in an inch, in either direction 2500 0.0037 0.0017 2.120 - 0.0737 0.0015 2.000 0.0001 0.0012 1350 - 0.0555 0.0010 1.500 " 0.0400 0.0000 1.250 0.0394 0.0004 1.000 0.0551 1.000 0.0210 0.075 0.0234 1.0" Numbet 4- Salve Size and Gradation - Sample Size and Gradation - Example 2 - Percent retained refers tO the percentage of the total that is retained - Using the following data, determine the percentage retained, on each sieve cumulative percentage retained. and percentage passing for each Cumulative percent retained refers to the sum of the percentage sIeve. retained on the sieve being considered plus the percentage retained TOW Weight _: Z[Weight_ Retainer?) _ on each coarser sieve Percent Retamed = (WeIght Retalned at Total Welght} x 100% Percent passing means the percentage Of the total weight that passes Cumulative Percent Retained x : Z[P_ercent Retained 9:0. 0:1) through the sieve under consideration. It is, therefore, the difference Percent P9155”; x Z 100% ' Cumulative Percent Retarned x between 100 percent and the cumulative percentage retained so far Problem 7c; Sieve Weight Percent Cumulative Percent Size (in) Retained (g) Retained Percent Passmg Retained 3 1.62 14.4% 14.4% 85.6% 2 2.1?r 19.3% 33.6% 66.4% 1 112 3.62 32.1% 65.7% 34.3% 3.14 2.2? 20.1% 85.9% 14.1% 318 1.38 12.2% 98.1% 1.9% Pan 0.21 1.9% 100.0% 0.0% Total weight = 11.2? 100% Conclusion Assignment Aggregate and Strength . Page 86 Compaction Review Questions 5, 6, 7a, & 7b Pavement Base DO NOT DO THE LAST HALF OF 7! Stabilizing Aggregate _ Permeability If you do not understand a question, Size and Gradiation email me at [email protected] or through myPHCCedu 02:0Fn—O 02.7JFn—O Uzi/F10 02.7JFn—O 1.42.202 1.42.202 1.42.202 1.42.202 Q7902 :m; N36 956 :oEm :mB :mEh :N; :ommd :mfi :Em omhé ~~.... \— ommd 000.? .2. OZ_meO |_<Z__>_Oz EBB 2 32% UB 8328 9%:me < cosmUEO Ucm mum - 3me ...
View Full Document

{[ snackBarMessage ]}