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THE HISTORY OF CIVIL ENGINEER

Sunday, November 22, 2020

Missing Search Person

 


Fine Material Specific Gravity

 


Sample for test.

A sample of about 1 kg for material having a nominal size from 10mm to 5mm inclusive, or about 500 g if finer than 5 mm, shall be used. Aggregates which have been artificially heated shall not normally be used. If such material is used, that fact shall be stated in the report. Two test shall be made.

The sample shall be thoroughly washes to remove all material finer than the 75 µm BS test sieve (5.5.1.7) using the following procedure.

Place the test sample in the container and add enough water to cover it. Agitate vigorously the contents of the container and immediately pour the wash water over the sieves, which have previously been wetted on both sides and arranged with the coarser sieve on top.

The agitation shall be sufficiently vigorous to result in the complete separation from the coarse particles of all particles finer than 75 µm BS test sieve, and to bring the fine material into suspension in order that it will be removed by decantation of the wash water. Take care to avoid, as far as possible, decantation of the coarse particles of the sample. Repeat the operation until the wash water is clean. Return all material retained on the sieves to the washed sample.

Saturday, November 21, 2020

Method for aggregates between 10 mm nominal size and smaller (Apparatus)

 


Apparatus

NOTE: All apparatus described should conform to the general requirements of BS 812: Part 100.

Balance, of capacity not less than 3 kg, accurate to 0.5g and of such a type as to permit the weighing of the vessel containing the aggregate and water.
Well ventilated oven, thermostatically controlled to maintain a temperature of 105 °C ± 5 °C+
Vessel, capable of holding 0.5kg to 1.0kg of material up to 10mm nominal size and capable of being filled with water to a constant volume with an accuracy of ± 0.5 ml. the following vessels are suitable
a)  Glass vessel, referred to last as a pycnometer, of about 11 capacity, having a metal conical screw top with an approximately 6 mm diameter hole at its apex. The screw top shall be watertight when it is screwed on to the jar, and, if necessary, a rubber or fiber washer shall be inserted in the joint. If such a washer is used, a mark shall be made on the jar to correspond with a mark on the screw top so that the screw is tightened to the same position every time and volume contained by the jar is constant throughout the test. A suitable vessel can be made from a 1kg fruit preserving jar in which the glass lid normally used is replaced by a sheet metal cone as shown in Figure 1.
b)  Wide-mouthed glass vessel, such as a gas jar, of 1.01 to 1.51 capacity, with a flat-ground lip and a plane-ground disc of plate glass to cover it, giving a watertight fit. 
Hair-dryer, or other means of supplying a current of warm air.
Watertight tray, of area not less than 0.03 m2.
Airtight container, large enough to take the sample.
Container, of a size sufficient to contain the sample covered with water and to permit vigorous agitation without loss of any part of the sample or water.
75 µm BS test sieve (see 5.4 of BS 812: Section 103.1: 1985) and a nesting sieve to protect the 75 µm test sieve, e.g. a 1.18 mm sieve.

Supply of water, free from any impurity that would significantly affect its density. If distilled or deionized water is not available in sufficient quantity, tap water which has been freshly boiled and cooled to room temperature may be used. This water shall be used throughout the test

Friday, November 20, 2020

Reporting of results

 


Reporting of results

The mean result shall be reported for each from of particle density determined, the title of which shall be quoted in full. In no circumstances shall the shortened title particle density be used in relation to any values quoted. The size of aggregate tested, and whether it has been artificially heated before the start of the test shall be started. The values of particle density shall be reported to the nearest 0.01 Mg/m3 and those for water absorption to the nearest 0.1 %      

Calculations For aggregates

 

Calculations

The particle density on an oven-dried basis (in Mg/m3) is calculated from the formula:

D/A-(B-C)

The particle density on a saturated and surface-dried basis (in Mg/m3) is calculated from the formula:

A/A-(B-C)




The apparent particle density (in Mg/m3) is calculated from the formula:

D/D-(B-C)

The water absorption (as % of dry mass) is calculated from the following formula:

100 (A-D)/D

Where

A       is the mass of the saturated surface-dry sample in air (in g);

B       is the mass of vessel containing sample and filled with water (in g);

C       is the mass of vessel filled with water only (in g);

D         is the mass of the oven-dry sample in air (in g);

Sample for test. (Test procedure)

 


Sample for test.

A sample of about 1 kg of the aggregate shall be used. Aggregates which have been artificially heated shall not normally be used; if such material is used, the fact shall be stated in the report. Two tests shall be made. The sample for test shall be thoroughly washed on the test sieve to remove finer particles and drained.

Test procedure

Immerse the prepared test sample In water in the glass vessel; it shall remain immersed at a temperature of 20° C ± 5° C for 24 h ± 0.5 h. Soon after immersion and again at the end of soaking period, remove air entrapped in, or bubbles on the surface of, the aggregate by gentle agitation. This may be achieved by rapid clockwise and anti-clockwise rotation of the vessel between the operator's hands.

Overfill the vessel by adding water and slide the plane-ground glass disc over the mouth so as to ensure that no air is trapped in the vessel. Then dry the vessel on the outside and weight it (mass B).

The empty the vessel and allow the aggregate to drain while the vessel is refilled with water, sliding the glass disc into position as before. Then dry the vessel on the outside and weigh it (mass C).

The difference in the temperature of the water in the vessel during first and second weighing shall not exceed 2° C.

Place the aggregate on a dry cloth and gently surface-dry it with the cloth, transferring it to a second dry cloth when the first will remove no further moisture. Then spread it out not more than one step deep on the second cloth and leave it exposed to the atmosphere away from direct sunlight or any other source of heat until all visible films of water are removed but aggregate still has a damp appearance. Weigh the aggregate (mass A) If the apparent particle density only is required the operations described in this paragraph may be omitted.

Place the aggregate in the shallow tray in the oven at a temperature of 105° C ± 5° C for 24 h ± 0.5 h.

Then cool it in the airtight container and weight it (mass D).If the particle density on a saturated and surface-dried basis only is required, the operations described in this paragraph may be omitted.

Method for aggregates between 40 mm and 5 mm (Apparatus)

 


Method for aggregates between 40 mm and 5 mm

Apparatus

NOTE: All apparatus described should conform to the general requirements of BS 812: Part 100.

Balance, of capacity not less than 3 kg, accurate to 0.5g and of such a type as to permit weighing of the vessel containing the aggregate and water.

Well ventilated oven, thermostatically controlled to maintain a temperature of 105 °C ± 5 °C+

Wide-mouthed glass, vessel, such as a gas jar, of 1.01 to 1.51 capacity, with a flat ground lip and a plane-ground disc of plate glass to cover it, giving a watertight fit.

Two dry soft absorbent cloths, each not less than 750 mm x 450mm.

Shallow tray, of area not less than 0.03 m2.

Airtight container, large enough to take the sample.

5.0 mm BS test sieve

Supply of water, free from any impurity that would significantly affect its density. If distilled or deionized water is not available in sufficient quantity, tap water which has been freshly boiled and cooled to room temperature may be used. This water shall be used throughout the test.

Wednesday, November 18, 2020

BSI is the independent national body responsible for preparing British Standards.


BSI- British Standards Institution

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Aggregate Testing

 






3 Reporting

3.1 General

The report shall affirm that the tests were done in accordance with this standard. Any departure from the specified test procedure shall be described with reasons for the departure and, if possible, estimates of its effect on the test results. The report shall also include details of any special processing of the sample, other than that required by the test methods, carried out in laboratory, e.g. crushing to provide larger quantities of smaller sizes or the separation of constituents from an as-dug gravel.

3.2 Certificate of sampling

The report shall affirm that a certificate of sampling was received with the sample and shall declare all the information given on the certificate. If a certificate was not received this shall be stated in the report.

4 Significance of results

The distribution of the result of any test on any material stems from a number of contributing factors. In assessing the significance of the results the repeatability and reproducibility of the test should be recognized. Estimates of these are given in annex A and should be used in assessing test results.

BS 812: PART2 : 1995

 

Methods

1 Scope

This Part of BS 812 describes methods for the determination of the particle density, water absorption, bulk density, voids and bulking of aggregates and of the particle density, bulk density and voids of filler.

Some of the tests are intended for use in obtaining assurance that material complies with British Standard or other requirements, for research, production control or assessment of variation. However, other methods are not intended for assurance testing and their suitability for other purposes is defined

NOTE. The density terms used are defined in clause 2 of BS 812: Part 100: 1990.

2
References

Normative references

This Part of BS 812 incorporates, by dated or undated reference, provisions from other publications. These normative reference are made at the appropriate places in the text and the cited publications are listed on the inside back cover. For dated references, only the edition cited applies; any subsequent amendments to or revisions of the cited publication apply to this BS 812 only when incorporated in the reference by amendment or revision. For undated references, the latest edition of the cited publication applies, together with any amendments.

2.2 Informative references

This Part of BS 812 refers to other publications that provided information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions.


Monday, November 16, 2020

Respect for pedestrians and cyclists

 



Respect for pedestrians and cyclists

Controlled pedestrian crossing are defined as all crossing controlled by a police officer or a traffic light. All other types of crossing are deemed as uncontrolled pedestrian crossing, even though a traffic signal may be flashing amber.

Avoid overtaking cyclists at intersections. Keep plenty of space from the cyclists for they often wobble.

Slow down and stop if you see that a pedestrian is waiting to cross the road.

Probable causes of pedestrian crossing accidents:

The driver did not notice or ignored the pedestrian at the side of the crossing.

The driver's view was obstructed, perhaps by the door post of his or her car.

The driver was going too fast and had insufficient time to watch the road, as he/she should

The driver overtook a vehicle that had stopped to allow a pedestrian to cross the road.

Road Marking


 
Road markings are used to qualify and clarify the rules and regulations enacted from federal law. They may warn of a danger, they may divide the road in to different lanes; they may separate a motor vehicle lane from a cycle track or pedestrian way; or they may signal some sort of prohibition.

Their advantage is that they can easily be seen when other signs are hidden by traffic and they can give a continuing message as you drive along the road.

As a general rule, the more paint, the more important the message.

Road markings appear as lines, continuous or broken, painted along or across the carriageway. In addition to lines, you will encounter arrows, studs, symbols and text messages.

A broken line functions as a recommendation, as a warning or as a guide for road users.

Continuous lines

Are prohibitive lines crossing or straddling a continuous line dividing two lanes is prohibited

Drivers must be familiar with all types of road markings.

You will find them illustrated in the appendix Road Markings.

 


3.2 Road Work

 



Road works

Road repairmen work under considerable pressure. Not only must they concentrate on their work, but they must also be on the constant lookout for oncoming traffic. So show consideration for people doing a tough job, slowdown in good time and keep well clear of the repair works site.

Some ways you can reduce risks on the road:

Keep a sufficient distance between yourself and the vehicle ahead.

Apply the three-second rule.

If someone is driving too close on your tail, take your foot of the acceleration and to increase the safety margin.

Be prepared for action at all times, i.e. by being extra whenever you think things could start getting dangerous.

Be prepared to brake, i.e. by moving your foot over to the brake pedal and being ready to stop in the shortest possible distance.


REFERENCED DOCUMENTS FOR GMB

REFERENCED DOCUMENTS

AASHTO Standard

           ·          M 231, Weighing Devices Used in the Testing of Materials

           ·          R 79, Vacuum Drying Compacted Asphalt Specimens

           ·          T 275, Bulk Specific Gravity of Compacted Asphalt Mixtures Using Paraffin- Coated Specimens

           ·          T 331, Bulk Specific Gravity and Density of Compacted Asphalt Mixtures Using Automatic Vacuum Sealing Method.

 

ASTM Standard

           ·          C6070, Standard Practice for Preparing Precision and Bias Statements for the Test Methods for Construction Materials

         E1, Standard Specification for ASTM Liquid-in-Glass Thermometers. 

APPARATUS. OF COMPACTED ASPHALT MIXTURE

 



APPARATUS.

Weighing Device---

The weighing device shall have sufficient capacity, be readable to 0.1 percent of the sample mass or better, and conform to the requirements of M 231.

Water Bath –

For immersing the specimen in water.

Thermometer—

ASTM 17C (17F) as provided in ASTM E1, having a range of 19 to 27°C (66 to 80° F), graduated in 0.1°C (0.2°F) subdivisions.

Volumeter—

Calibrated to 1200 Ml, or an appropriate capacity depending on the size of the test sample, the volumeter shall have a tapered lid with a capillary bore.

Sunday, November 15, 2020

Standard Method of Test for Bulk Specific Gravity (Gmb) of Compacted Asphalt Mixtures Using Saturated Surface-Dry Specimens

          


               SCOPE

Ø  This method of test covers the determination of bulk specific gravity (Gmb) of specimens of compacted asphalt mixtures.

Ø  This method should not be used with samples that contain open or interconnecting voids or absorb more than 2.0 percent of water by volume, as determined in Section 7.2 or 10.2 herein. If the sample contains open or interconnecting voids or absorbs more than 2.0 percent of water by volume, then T 275 or T 331 should be used.

Ø  The bulk specific gravity (Gmb) of the compacted asphalt mixture may be used in calculating the unit mass of mixture.

Ø  Note 1- The values for bulk specific gravity (Gmb) obtained from T 275 or T 331 may differ. Care should be exercised when comparing test result from T 275 or T 331.

 

Ø  The values stated in SI units are to be regarded as the standard.

 

Ø  This standard may involve hazardous materials, operations, and equipment. This standard does b not purport to address all the safety concerns, if any, associated with its used. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

وفاقی وزیراطلاعات شبلی فرازکی اسلام آباد میں پریس کانفرنس سے خطاب

 


گلگت بلتستا ن ا لیکشن صاف اور شفاف ہو گے۔۔۔وفاقی وزیراطلاعات شبلی فراز                                                

گلگت بلتستا ن انتخابات:اپوزیشن اپنی ہار کو دیکھ دھاندلی کا شور مچارہی ہے اپوزیشن کے لئے صرف ایسے ا نتخابات شفاف ہوتے ہیں،جن میں جیتے ہیں صاف اور شفاف الیکشن کو یقینی بنائیں گے وفاقی وزیراطلاعات شبلی فرازکی اسلام آباد میں پریس کانفرنس سے خطاب۔۔۔۔

 اسلام آباد(بورے والاٹوڈئے۔۔۔14نومبر2020ء)  وفاقی وزیراطلاعات ونشریات شبلی فرازنے کہاکہ گلگت بلتستا ن انتخابات میں متوقع ہار کی وجہ سے اپوزیشن دھاندلی کا شور مچارہی ہے،ُٓاپوزیشن کے لئے صرف ایسے ا نتخابات شفاف ہوتے ہیں،جن میں جیتے ہیں صاف اور شفاف الیکشن کو یقینی بنائیں گے۔ وفاقی وزیراطلاعات شبلی فرازنے اسلام آباد میں پریس کانفرنس سے خطاب کرتے ہوئے کہا کہ سب سے پہلے میں گلگت بلتستا ن کی عوام کا شکریہ ادا کرتا ہوں،جس طرح انہوں نے انتخابی مہم کو چلایااور مہم میں حصہ لیااور وہاں پر امن وامان قائم رکھاجسکا حکومت کی طرف سے شکریہ ادا کرناچاہتا ہوں۔

 


Saturday, November 14, 2020

CBR test Calculation

 


CALCULATIONS

Stress-Strain Curve –Plot the stress (resistance to penetration-depth of penetration) curve for each specimen as shown in Figure2. In Some instances, the initial penetration takes place without a proportional increase in the resistance to penetration and the curve may be concave upward. To obtain the true stress-strain relationships, correct the curve having concave upward shape near the origin by adjusting the location of the origin by extending the straight-line portion of the stress-strain curve downward until it intersect the abscissa (see dashed lines)

California Bearing Ratio- The corrected load values shall be determines for each specimen at 2.54 and 5.08 mm (0.10 and 0.20 in.) Penetration. California Bearing Ratio values are obtained in percent by dividing the corrected load values at 2.54 and 5.08 mm by the standard loads of 6.9 and 10.3 MPa (100 and 500 psi), respectively, and multiplying these ratios by 100.

 

 

CBR = corrected load value x100/

Standard Load

 

The CBR is generally selected at 2.54 mm (0.10 in.) penetration. If the ratio at 5.08 mm (0.20 in.) penetration is greater, the test shall be rerun. If the check test gives a similar result, the ratio at 5.08 mm (0.02 in.) penetration shall be used.

PENETRATION TEST FOR SOIL

 

PENETRATION TEST

Application of One Surcharge Weight- Place one annular weight on the specimen. Seat the penetration piston with a load of no more than 44N (10 lb.)

Application of the Remaining Surcharge Weight- After seating the penetration piston, place the remainder of the surcharge weight around the piston. The total amount of surcharge weight placed on the specimen shall be equal to the surcharge weight used during soaking. Set the penetration dial indicator and the load indicator to zero.

Application of Load-Apply the loads to the penetration piston so the rate of penetration is uniform at 1.3 mm (0.05 in.)/ mm. Record the load when the penetration is

0.64

1.27

1.91

2.54

3.81

5.08

7.62

Load readings at penetrations of 10.16 and 12.70 mm (0.400 and 0.500 in.) may be obtained is desired.

Note1---The moisture content of the upper 25 mm (1 in). May be determined after testingif desired. Moisture samples shall weight at least 100 g for fine-grained soilsand 500 g for granular soils.

Thursday, November 12, 2020

Relation between Dry Density and Moisture Content


 

MOISTURE-DENSITY RELATION

Bearing Ratio at Optimum Water Content-Using the 11-kg (25-lb.) portion prepared as described in section 5.1, determine the optimum moisture content and maximum dry density in accordance with the compaction method specified, either T99 or T180. A previously performed compaction test on the same material may be substituted for the compaction test just described, provided that if the sample contains material retained on the  19.0-mm (3/4 in) sieve, soil prepared as described in section 5.1 is used (Note 3).

Note 3 –Maximum dry unit mass obtained from a compaction test performed in a 101.6-mm (4 in.) diameter mold may be slightly greater than the maximum dry unit weight obtained from compaction in the 154.2-mm (6-in.) compaction mold or CBR mold.

Bearing Ration for a Range of Water Content- Using the 6.8-kg (15-lb) specimens prepared as described in section 5.1, determine the optimum moisture content and maximum dry density in accordance with the compaction method specified, either T99 (Method D) or T 180 (Method D), except that the CBR molds shall be used and each specimen shall be penetrated for CBR determination. In addition, the complete moisture-density relationship for 25-bolows ad 10-bolows per layer compaction shall be developed and each test specimen compacted shall be penetrated. Perform all compaction in CBR molds. In cases where the specified unit mass is at or near 100-percent maximum dry unit mass, it will be necessary to include a comp active effort greater than 56 blows per layer (Note 4).

Note-4 A semilog plot of dry unit mass versus compactive effort usually gives a straight-line relation when compactive effort in J/m3 (ft-lb/ft3) is plotted on the log scale. This type of plot is useful in establishing the compactive effort and number of blows per layer needed to bracket the specified dry unit mass and water content range.

If the soaked CBR is to be determined, take a representative sample of the material, fir the determination of moisture, at the beginning of compaction of each specimen and another sample of the remaining material after compaction of each specimen. Use T 265 to determine the moisture content. If the unsoaked CBR is to be determined, take a moisture content sample in accordance with T 99 or T 180 if the average moisture content is desired.

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