What is your recommendation for the maximum size of coarse aggregate for the following situation? A continuously reinforced concrete pavement cross section contains a layer of No. 6 reinforcing bars at 6-in. centers, such that the steel is just above mid-depth of a 10-in. thick slab. Cover over the top of the steel is therefore about 4 in.

6. Discuss the different types of volume change in concrete at early and long-term ages.

Explain why shape, surface texture, and gradation are more important for aggregate use in normal strength concrete than strength and origin of rock formation.

what are the effects of aggregates in the performance of concrete?

Help me with this.

Tennis court, subjected to freezing Required design strength =21 MPa Slab thickness=300 mm Statistical data indicate a standard deviation of compressive strength of 3.7 MPa is expected (for 50 samples) Only air entrainer is allowed Available materials: Air=7% Air entertainer: Manufacturer specification is 9.0 ML /1% air/100kg cement Slump=50 mm Coarse aggregate: 50 mm nominal maximum size, crushed stone Bulk volume oven-dry specific gravity=2.61, absorption=2.8%, oven-dry rodded density=1870 kg/m3 Moisture content=1% Fine aggregate: Natural sand Bulk oven-dry specific gravity=2.54, absorption=3.4% Moisture content= 4.5% Fineness modulus=2.60 Cement: Type I, relative density=3.1 What is the maximum coarse aggregate size?

Design the concrete mix according to the following conditions:  Design environment Tennis court, subjected to freezing Required design strength =21 MPa Slab thickness=300 mm Statistical data indicate a standard deviation of compressive strength of 3.7 MPa is expected (for 50 samples) Only air entrainer is allowed Available materials: Air=7% Air entertainer: Manufacturer specification is 9.0 ML /1% air/100kg cement Slump=50 mm Coarse aggregate: 50 mm nominal maximum size, crushed stone Bulk volume oven-dry specific gravity=2.61, absorption=2.8%, oven-dry rodded density=1870 kg/m3 Moisture content=1% Fine aggregate: Natural sand Bulk oven-dry specific gravity=2.54, absorption=3.4% Moisture content= 4.5% Fineness modulus=2.60 Cement: Type I, relative density=3.1

Concrete is required for a column that will be Severe Exposure to freezing and thawing. The cross section of the column is 300 × 300 mm. The smallest spacing between reinforcing steel is 40 mm. The specified compressive strength of concrete at 28 days is 40 MPa with a slump of 25 to 50 mm. The properties of materials are as follows: (a) Cement used is type I Portland cement with a specific gravity of 3.10. (b) The available coarse aggregate has a maximum size of 23 mm, a dry-rodded unit weight of 1800 kg/m3, a bulk specific gravity (SSD) of 2.68, absorption capacity of 0.65%, and moisture content (SSD) of 0.27%. (c) The fine aggregate has a bulk specific gravity (SSD) of 2.75, absorption capacity of 1.5%, a moisture content (SSD) of 2.5%, and a fineness modulus of 2.7,The aggregates conform to the ASTM C33-84 requirements for grading.

What is the value of the Whitney stress block parameter, β1β1, for 6000 psi concrete?

Correctly define which of the stress versus strain graphs represent the comparison of 8 ksi and 4 ksi concrete for the chart below (say left or right). Qualitatively compare the w/c ratio, elastic modulus, and brittleness. 0.000 0.003 0.000 0.003 Sean, e Sane Feure 2 Strss vesus Srain curves Feure 2. Stress vasus rain curve