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THE HISTORY OF CIVIL ENGINEER

Monday, December 7, 2020

Basic positioning when turning right

 


 

Basic positioning when turning right

Drivers intending to turn right should keep their vehicles as close to the right-hand edge of the carriageway as is appropriate for traffic conditions.

Position your car and turn off, keeping as far to the right as possible. This not only makes it easier for the vehicles on your left but also prevents drivers from creeping up on your right. After turning off, position yourself as appropriate for your ongoing itinerary.

It goes without saying that, in streets with two-way traffic with just one lane in each direction, you must keep well to the right so as to allow plenty of room for oncoming traffic.

Right-Hand Traffic (UAE)

 


Right-hand traffic

One two way traffic roads a vehicle should be driven in the lane furthest to the right, as seen from the direction of travel.

Keep to the right, leaving plenty of space for any fast-moving vehicles.

Always try to position your car so that you can handle unexpected overtaking and sudden meetings with oncoming traffic with maximum safety.

Overtaking and meetings with oncoming vehicles always involve an element of risk. If visibility is poor, as it may be if your view is obscured by a hill or a bend in the road, or if you are driving at night or in fog or rain, the risk is greatly enhanced.


Friday, December 4, 2020

Basic positioning when continuing straight ahead

 


Basic positioning when continuing straight ahead

Whenever possible, get into the right-hand lane if you intend to continue in the direction you are traveling. At or just before the junction you will have to keep to the right, even though you may have to negotiate with parked cars.

Saturday, November 28, 2020

The Vehicle

 


The road

Naturally, you must also adapt your speed to the condition of the road you are driving on. On gravel roads, the braking distance is much longer than on asphalt, and a wet asphalt road is more slippery than a dry one. Teach yourself to 'read' the road and predict where danger might lurk: at bends, on hills, on wet patches, and many other places.

The vehicle 

Performance varies greatly from one car to the next and even more so from motorcycle to motorcycle so, if you borrow a vehicle you're unfamiliar with, make sure you take things easy. 

UAE Road Speed Limit



Never allow speed to get the upper hand. Stay in control of your car at all times. Many drivers overestimate their own abilities and drive dangerously fast. This is why single-vehicle accidents are the most common type of accident on main roads outside built-up areas.

Always adapt to local traffic conditions.

The maximum speed limit in the major roads in UAE is 40 km/h inside the city, the speed limit is usually 80 km/h, outside built-up areas, and the standard speed limits is 100 km/h. 

Fortunately, the recipe for avoiding collisions is simple:

 


Fortunately, the recipe for avoiding collisions is simple:

Anticipate, observe, adapt.

Hidden danger

As you travel down the road, you must be able to bring your vehicle to a half well before reaching an obstacle on the road ahead. Weather real or potential. As a driver, you must teach yourself to predict what could be hidden behind a parked car, behind a hedge or round the next bend. This ability comes only with practice.

Things to consider when leaving town.......







Things to consider when leaving town.......

Speed limits

Driving speed must never exceed the speed at which the driver can maintain safe control of the vehicle and bring it to a half on the carriageway or hard shoulder

This means that the distance needed to slow the car to a half must be clear and free of any visible or anticipated obstacle the road ahead.

Adapting your speed

You must also adapt your speed to the state of the traffic, the weather, visibility, the weight of your load, the condition of your vehicle, and, above all, your own abilities. Do not base you're driving on what you think. Base it on what you see and on what you know.

Major roads mean high speeds. And high speeds are perfectly acceptable provided nothing gets in the way. Remember that hitting another vehicle at 40 km/h, which is not particularly fast, is equivalent to falling onto a concrete floor from a height of 10 meters for the occupants of the vehicles involved, the impact is murderous. 

Monday, November 23, 2020

Apparatus for Bitumen Distributors Test

 


Significance and Use

The amount of bituminous material applied to a pavement surface using a bituminous distributor can be estimated using the described procedure.

Apparatus

Test Method A and B:

Balance, sensitive to 0.1g.

Weighing Box or Balance Shield, to protect balance from wind when the balance is in use at the project site (See Figure 1).

Balance Table and work Table, for weighing.

Test Method B:

Elliptical Containers, measuring approximately 3.5 in. (88.9 mm) along the short axis and 9 in. ( 228.6 mm) in height, capable of an internal volume of approximately 1 gal.

Rubber Bands, capable of a snug fit when stretched around the elliptical containers.

Stopwatch, Capable of recording to the nearest 0.1 s.

Materials

Test Method A:

 Geotextile Pads, weighing a minimum of 8 oz. /yd2 and measuring 12 in. (304.8 mm) by 12 in. (304.8 mm)

Aluminized Duct Tape, measuring 2 in (50.8 mm) wide and 6 in. (152.4 mm) long.

Butcher Paper #50, measuring 30 in. (762 mm) by 950ft, for temporary protection of geotextile pads during calibration.

Test Method B:

Plastic Bags, capable of fitting inside the elliptical cans but of sufficiently larger dimension to allow folding over the edge of the elliptical containers once placed inside.

Standard Practice for Estimating Application Rate of Bitumen Distributors1

Scope 

This practice covers the determination of transvers and longitudinal application rate of asphalt distributors in gallons per square yard (or liters per square meter).

This standard does not purport to address all of the safety concerns, if any, associated with it use. 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.

The values given in inch-pound units are to be regarded as the standard. The SI values given in parentheses are for information purposes only.

Summary of Practice

Test Method A:

Pre-weighed calibration pads are placed on the surface of the roadway in front of the distributor to be calibrated. The asphalt distributor to be calibrated is driven over the calibration pads while spraying asphalt. The calibration pads are removed from the roadway any reweighed. The weight of asphalt applied to the pads is determined by subtraction and the rate of application is calculated.

Test Method B:

Containers are placed under each nozzle of a bituminous distributor and bituminous material is sprayed into the containers for a known period of time. The volume of bituminous material sprayed after this period is calculated. The transverse uniformity of bituminous material sprayed on the pavement is obtained from this calculation and the distribution of bituminous material applied longitudinally on the pavement is calculated as a function of the distributor velocity 

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.


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