What is deleterious material?
Deleterious materials (also known as prohibited materials) are materials that are prohibited for use in a project. This could be for a variety of reasons including: reliability. health and safety. structural stability/performance/physical integrity/life-expectancy of a project.
What are deleterious materials in aggregates?
Deleterious materials in aggregate are those substances which detrimentally effect the fresh and hardened properties of concrete for instance strength, workability, and long-term performance of the concrete in which such are used. Deleterious materials and highly undesirable constituents.
Which material is most deleterious?
Asbestos
Asbestos – Asbestos is the most written about deleterious material; Please see our other blogs for information on asbestos hazards and management.
Is a deleterious material in concrete aggregates?
Deleterious materials are essentially the same as those found in coarse aggregates consisting of clay lumps, shale, soft, friable, or laminated particles, vegetable matter, or other objectionable material.
What is deleterious effect?
Definition of deleterious : harmful often in a subtle or unexpected way deleterious effects deleterious to health.
What is bulking of sand?
Bulking of fine aggregate or sand is the phenomenon of increase in sand volume due to the increase of moisture content. Bulking test on fine aggregates has to be performed before using it in construction. This article describes the procedure and importance of determining bulking of fine aggregates.
What are the impurities in aggregate?
Organic impurities, usually in the form of tannic acid and its derivatives, are typically present in fine aggregates such as sand. These may interfere with the chemical reaction of hydration and may effect the strength of the mortar or concrete where the aggregates are used.
What are deleterious materials in concrete?
Certain chemical contaminants such as soluble chlorides and sulphates, organic compounds such as mono- and polysaccharides, humic acid and lignins, and also soluble salts of lead, zinc, cadmium and tin, can retard the setting of cement, and hence affect the final strength and durability of concrete.
What is Woodwool shuttering?
Woodwool is a man-made board material about 50 to 75mm thick comprising shredded timber bound together in a cement paste. It was used generally during the 1960s to provide insulation often at roof level and as a permanent shutter to in-situ concrete.
What is soundness test aggregate?
Soundness is the percentage loss of material from an aggregate blend during the sodium or magnesium sulfate soundness test. This test, which is specified in ASTM C88 and AASHTO T104, estimates the resistance of aggregate to in-service weathering. It can be performed on both coarse and fine aggregate.
What is the most accurate total deleterious material model?
TOTAL DELETERIOUS MATERIALS (TDM) MODELS The most accurate TDM model [Model 1-a] (adjusted R2= 0.856) entailed two tests performed routinely by MoDOT (MD and PI), and two tests that are not currently being performed (PLSdryand Isd2). The PLSdrywas also recommended in a recent study for MoDOT that dealt with prediction of AASHTO T 161 results.
What is a “deleterious material”?
Deleterious Materials means any materials or substances which in the particular circumstances in which they are to be used fail to satisfy the relevant British Standard and the principles of good building practice ( including the essential requirements defined in the Construction Products Regulations 1991).
What are the deleterious materials in concrete?
Commonly deleterious materials are organic matters, dust (materials passing through 75 micron sieve), clay lumps, shale, coal iron pyrites, friable particles, chert (weak in terms of freezing and thawing), etc. which are weak, soft and fine. They affect the properties of concrete in fresh as well as in hardened state and are undesirable.
How do you measure the amount and nature of deleterious materials?
There are several methods for estimation of the amount and nature of deleterious materials such as clay and organic matter. One of the simplest is AASHTO T 330, the methylene blue test (AASHTO, 2007).