the deleterious material present in the aggregate

Impurities which interfere with the process of hydration of cement. Measuring specific gravity key steps: -determine saturated surface dry mass (SSD) -determine oven dry mass (OD) -determine volume of sample. Determination of Clay Lumps in Aggregate, IS: 2386 (Part-2)–1963. Coal and lignite may also cause staining of exposed concrete surfaces. ings of clay, and other fine materials in amounts that could affect hydration and bond of the cement paste. Deleterious materials in construction - Designing Buildings Wiki - Share your construction industry knowledge. natural and manufactured/processed. For fine aggregate: 15 % when sodium sulfate is used or 20 % when magnesium sulfate is used. This requirement is only to be reported when such material is present. (d) The amount of deleterious substances shall not exceed the following limits: Maximum Permissible Limits, By Weight 1. The total amount of deleterious materials in aggregate should not exceed 5% as per IS 383-1970. 1. The sum of percentage of all deleterious materials in the aggregate shall not exceed (a) 5% (Ans) (b) 10% (c) 15% (d) 20%. These substances or materials are normally referred to as deleterious materials. Effect of presence of various deleterious materials on concrete are tabulated below. *Limits for deleterious substances not listed in this Table, such as coal, ochre (ironstone), shalestone, siltstone, or argillaceous limestone, shall be specified by the owner to encompass deleterious materials known to be present in a particular region. A typical rinsing set-up would be used when the material does not require scrubbing, only rinsing to remove small particles of silt and fines to produce a clean end-product. Size: The size of fine aggregate should be equal to or less than 4.75 mm. Table 4: Harmful Material in Aggregate deleterious Substances Effect on Portland cement concrete Organic impurities May delay setting and hardening of concrete, may reduce strength gain, and … 3. Careful production is required. -THEY ARE HARMFUL TO CONCRETE PERFORMANCE. options (models) were open to MoDOT for consideration for each type of deleterious material (Total Deleterious Material, Total Deleterious Material Plus Hard Chert, Deleterious Rock Plus Soft Chert, and Shale). It is intended to be used to identify materials that are soft and to identify other types of deleterious materials in aggregates. classified as deleterious and the Specification limits for each. similar materials quality tests—namely, Sand Equivalent and L.A. Abrasion, whereas VDOT uses Soundness, Void Content, Organic Impurities and Deleterious Materials, which may aid in the use of a durable, non- reactive and long-lasting aggregate. ASR is the most common form of alkali-aggregate reaction (AAR) in concrete; the other, much less common, form is alkali-carbonate reaction (ACR). Production of aggregate is expected to reach 2.5 billion tons by 2020, which raises concerns about where the new aggregate will come from. Deleterious materials may cause one of the following effects To interfere hydration of cement Aggregate properties significantly affect the workability of plastic When combinations of materials for Class B aggregate for mineral aggregate base and surface courses such as creek gravel Aggregates containing any appreciable amounts of shale or other shaly rocks, soft and porous materials, Fig. 2. If steel reinforcement is present in the affected area, corrosion is likely to occur. Aggregates are generally classified into two categories viz. Aggregate particles that are friable or capable of being split are unde-sirable. 2386 Part VII-1963. 1029.01 Scope. In addition, the cracks will allow carbon dioxide to penetrate deep into the concrete as gas or dissolved in rain water, initiating carbonation at depth within the concrete. Ozinga Bros. Inc., a ready-mix producer in Chicago, is working with the Chicago DOT on its Green Mile Project. Alkali-aggregate reactivity test on aggregate, and alkali-aggregate reactivity test using concrete were conducted to investigate inhibiting effect of GGBFS for HSC. deleterious material in aggregate and is a specification require­ ment without association to any other property and without suf­ ficient information to show that softness, per se, is in fact a deleterious property of aggregate. 0.3 The limiting values for the permissible deleterious materials in the aggregates, aggregate abrasion value and soundness test for aggregates have been revised, Recommendations have been included for the size of aggregates for mass concrete. Method of Deleterious material test of aggregate by routine examination. NOTE: The maximum quantity of deleterious materials should not be more than 5% of the weight of the aggregate when determined in accordance with IS: 2386(I). Hi friends, you are welcomed in the world of Civil Allied Gyan.Read definition, apparatus, IS code, test procedure, formula, result and lab report of Determination of Clay Lumps in Aggregate as per IS 2386-2-1963.. IS Code for Determination of Clay Lumps:-. Alkali-aggregate reaction is defined as the reaction between the alkaline hydroxide present in the cement and reactive silica or carbonates present in certain aggregates to form a gel. Vegetation, soft particles, clay lumps, excess dust and vegetable matter are not desirable because they generally affect performance by quickly degrading, which causes a loss of structural support and/or prevents binder-aggregate bonding. Deleterious rock includes the following materials: (1) Shaly rock. Data are presented that relate the scratch hardness test in terms of Mohs hardness which aggregate particles are embedded. The potential reactivity of aggregate can be determined as suggested by I.S. Introducing reclaimed concrete aggregate (RCA) into concrete, however, requires the use of quality control and quality assurance procedures to ensure that deleterious materials that might be present in the reclaimed concrete aggregate will not adversely impact the quality of … Method of Deleterious material test of aggregate by routine examination. Deleterious materials mean aggregate properties that can cause of effect on the strength and durability of the concrete. More specifically, the impurities can impact the hydration of the material. Source: Table 1 Limits for Deleterious Substances in Fine Aggregate for Concrete, ASTM C 33. Uncontrolled fill materials encountered during a geotechnical engineering exploration or during construction present unique challenges unlike issues associated with naturally-occurring soil deposits. 5-1. The harmful material in any construction is called Deleterious material. For coarse aggregate: 12 % when sodium sulfate is used or 18 % when magnesium sulfate is used. The four grading zones for fine aggregates Shape of the aggregate plays a more important role in coarse aggregate rather than fine aggregate. effects of the deleterious material, if present, on the properties of green or hardened concrete. Deleterious materials mean aggregate properties that can cause of effect on the strength and durability of the concrete. Impurities in Aggregates (soft particles, chert, clay lumps and coal, lignite, or other lightweight materials) are change the setting times and rates of hardening of concrete. Aggregates must be relatively clean when used in HMA or PCC. material from Section 4.7, calculate the percent of deleterious material in aggregate: Percent Deleterious W W W W W= +++100 ()/12 3 4T Where: WT = mass of total test sample W1–4 = individual fractions of deleterious material. The total blended aggregate from the fine and coarse aggregates, and recycled materials used in HMA are required to meet the fine aggregate angularity (FAA) requirements of Section 904.02(b). This is due to a chemical reaction that can cause pyritic backfill to swell. Petrographic classification of rock type need not be reported. Crushed aggregates have a rough texture and give a good mechanical bond with cement. 7 Deleterious material Water demand (strength), bond, cohesion and durability Surface texture of aggregate influences the bond between the aggregate and cement. 3. Coatings of Clay, Silt and crusher dust, etc., present in the form of surface coatings interfere with the bond between the aggregates and the cement paste. Deleterious Materials in Concrete Research Study 2-5-63-71 Sponsored by The Texas Highway Department In Cooperation with the U.S. Department of Commerce, Bureau of Public Roads March, 1967 TEXAS TRANSPORTATION INSTITUTE ... tually present in an aggregate. This test is done utilizing the procedure set forth by ASTM C 40. The chemical reaction between alkalis in cement and reactive silica constituents present in aggregate is known as ASR, which produces a gel reaction product that swells when it imbibes water. Deleterious Substance in Aggregates: Deleterious substances can be classified into the following three categories: 1. Table 2: Deleterious Substance in Fine Aggregate If the organic impurities exceed the prescribed limits, the aggregates shall be subjected to the test for organic contaminants and producing a color darker than the standard shall be rejected provided that discoloration is due to … Specific Gravity. Furnish steel slag with less than 3 percent deleterious substances (soft pieces) by weight. Deleterious substances are those, which if present in aggregate makes concrete loss its strength, durability, performance etc. Aggregate in general consists of both fine and coarse inert materials used in the manufacture of concrete. As an alternate to the regression models, a threshold-limits method was presented. 8 (2.36 mm) sieve for compliance with the deleterious material requirements if the sample contains an aggregate that predominately passes the No. •common value of 2.65. 2. The material from which the fine aggregate is processed shall have a percentage of wear, Los Angeles Test, of not more than forty. The impurity content was less than 1% for RCAs obtained from different states (CO, OH, TX, MN, CA, MI, WI, and NJ). IS: 2386 Part-2 (1963) covers an approximate method of estimating the organic impurities and deleterious materials, whether organic compounds are present in natural sand in sufficient quantities to be harmful, and hence is intended to show whether further tests are necessary or desirable. Fine aggregate is aggregate all of which passes through 4.75 mm IS sieve. The resistance of an aggregate to compressive forces is known as (a) crushing value(Ans) (b) impact value (c) abrasion value (d) none of these. Geologically aggregates may be obtained from

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