6.31 A concrete mix includes the following ingredients per cubic foot: 5463 a. Cement = 25 lb b. Water 11 lb c. No admixture Table P6.31 shows possible changes that can be made to the mix ingredi- ents. Indicate in the appropriate boxes in the table what will happen in each case for the workability and the ultimate compressive strength as increase, decrease, or approximately the same. TABLE P6.31 = Cement (lb) 25 28 25 25 25 25 25 granula VID00 Water (lb) 15 11 11 8 11 11 11 Admixture None None Water reducer Water reducer Superplasticizer Air entrainer Accelerator xe pola What Will Happen? Workability Ultimate Compressive Strength

6.31 A concrete mix includes the following ingredients per cubic foot: 5463 a. Cement = 25 lb b. Water 11 lb c. No admixture Table P6.31 shows possible changes that can be made to the mix ingredi- ents. Indicate in the appropriate boxes in the table what will happen in each case for the workability and the ultimate compressive strength as increase, decrease, or approximately the same. TABLE P6.31 = Cement (lb) 25 28 25 25 25 25 25 granula VID00 Water (lb) 15 11 11 8 11 11 11 Admixture None None Water reducer Water reducer Superplasticizer Air entrainer Accelerator xe pola What Will Happen? Workability Ultimate Compressive Strength

Materials Science And Engineering Properties

1st Edition

ISBN:9781111988609

Author:Charles Gilmore

Publisher:Charles Gilmore

Chapter12: Composite Materials

Section: Chapter Questions

Problem 12.7P: Estimate the transverse tensile strength of the concrete in Problem 12.6.

See similar textbooks

Similar questions

A concrete mix includes the following ingredients per cubic meter: a. Cement = 400 kg b. Water = 176 kg c. No admixture Table P6.30 shows possible changes that can be made to the mix ingredi- ents. Indicate in the appropriate boxes in the table what will happen in each case for the workability and the ultimate compressive strength as increase, decrease, or approximately the same.
Problem 2: If f = 3 ksi what is the modulus of elasticity Ec and the maximum tensile stress fr that the concrete can carry before cracking (use ACI recommended equations). Assume a unit weight of the plain concrete is: a. Wc = 90- b. w lb lb 118- ft39 ft3) C. W = 160- Problem 3: Wight 3-6 Rugblom 4: Wight ? 7 lb ft3
5 - please show correct and complete solution, thanks!
a 250mmx500 concrete be am is to be reinforced with 5-28mm diameter bars at tension sde. For the web-reinforcement,10mm dimater bar was used (Cc=40mm). Using 19mm diameter aggregates for the concrete mix. 1.Determine the minimum clear spacing of main bars (horizontal layer) as prescribed by the code. a. 25mm b.28mm c.19mm d.32mm 2 .Determine the minimum clear spacing of main bars (Vertical layer) as prescribed by the code. a. 25mm b.28mm c.19mm d.32mm 3. What is the effective depth of the beam a.430 b. 426 c.415 d.405 Answers. 28,25,415
Concrete technology (lab)
What is your recommendation for the maximum size of coarse aggregate for a column 500X500 mm if the minimum clear distance between reinforcement bars is 50 mm and the minimum cover is 40 mm. Select one: A. 12.5 mm B. 25 mm C. 37.5 mm D. 19 mm
A concrete mix includes the following ingredients per cubic meter: Cement%3D400 kg Water=184 kg No admixture Table below shows possible alternatives mix ingredients. Indicate in the appropriate boxes in the table what will happen in each case for the workability and the ultimate compressive strength as increase, decrease or approximately the same. What will happen? Cement Water Admixture (kg) (kg) Ultimate compressive Workability strength 400 225 None 449 184 None Water 400 184 Reducer Water 400 128 Reducer 400 184 Super Plasticizer 400 184 Air Entrainer 400 184 Accelerator DFocus
7.8 Design the concrete mix according to the following conditions: Design Environment Building frame Required design strength Minimum dimension 27.6 MPa || 150 mm Minimum space between rebar Minimum cover over rebar Statistical data indicate a standard deviation of compressive strength of 2.1 MPa is expected (more than 30 samples). Only air entrainer is allowed. 40 mm = 40 mm Available Materials Air entrainer: Manufacture specification 6.3 ml/1% air/100 kg cement. Coarse aggregate: 19 mm nominal maximum size, river gravel (rounded) Bulk oven-dry specific gravity Oven-dry rodded density Moisture content = 2.5% 2.55, Absorption = 0.3% = 1761 kg/m³ Fine aggregate: Natural sand Bulk oven-dry specific gravity 2.659, Absorption 0.5% Moisture content = 2% Fineness modulus 2.47 %3D
Contraction joints: O A All of the above O B) Allow the concrete to move both horizontally and vertically OC) Minimize random cracks O D) Should be cut to a depth of one-half the slab thickness The most common method for placing concrete for sidewalks is O A) Buckets and Cranes O B) Chutes OC) Conveyors O D) Pumping What is the effect on the properties of hardened concrete if plastic concrete freezes for an extended period after placing? OA) All properties will be enhanced in quality O B) No effect on concrete properties OC) All properties will be reduced in quality O D) Concrete strength decreases but freeze/thaw resistance increases Bull floating is done: OA Immediately after hand floating O B) Immediately after bleed water has evaporated OC Before screeding O D) Immediately after screeding
7.8 Design the concrete mix according to the following conditions: Design Environment Building frame Required design strength = 27.6 MPa Minimum dimension = 150 mm Minimum space between rebar = 40 mm Minimum cover over rebar = 40 mm Statistical data indicate a standard deviation of compressive strength of 2.1 MPa is expected (more than 30 samples). Only air entrainer is allowed. Available Materials Air entrainer: Manufacture specification 6.3 ml/1% air/100 kg cement. Coarse aggregate: 19 mm nominal maximum size, river gravel (rounded) Bulk oven-dry specific gravity = 2.55, absorption = 3.6% Oven-dry rodded density = 1761 kg/m³ Moisture content = 2.5% Fine aggregate: Natural sand Bulk oven-dry specific gravity Moisture content = 2% Fineness modulus = 2.47 = 2.659, absorption = 0.5%
Q. Using the British methods, design a concrete mix to bear an average compressive strength of 35 MPa at 28 days, to cast a room slab with the following dimensions (5 width x 4 length x 0.2 depth m) and 200 mm space distance of reinforcement. Consider the following properties: o Cement used is type I Portland cement ® Required slump = 30 — 60 mm o Coarse aggregate: ® Crushed rocks * Maximum size of 40 mm, e The fine aggregate: * Crushed rocks = Falls in zone 3 o Assume zone A for figure 1 o AssumeK = 1.64
Select the series which is expected to give higher compressive strength and write the necessary explanations for each parameter in the following table. Explanation about Concrete 1st Concrete 2nd Concrete Series Selected Series Explanation and Series (1 or 2) Materials Select the concrete series which is expected give higher compressive strength at 7 to CEM I 32.5 N CEM 1 32.5 R ... days by considering the cement properties. Water amount, C35: 40%, C25: 30%, aggregate, admixtures, labour C35: 52%, C25: 19%, and C3A:10%, CAAF: C3A: 996, CAAF: 12% curing conditions Activate Windows 11%