SAND EQUIVALENT TEST.


SAND EQUIVALENT TEST.
( IS : 2720 – PART – 37 )

INTRODUCTION:
This test is intended to serve as a rapid field test to show the relative proportions of fine dust or clay like material in soils or graded aggregates.

Apparatus:
1) A graduated plastic cylinder, rubber stopper, irrigator tube, weighted foot assembly, and siphon assembly, all confirming to their respective specifications and dimensions. Fit the siphon assembly to a 4 liters bottle of working calcium chloride solution placed on a shelf 915 +/- 25mm above the work surface. In lieu of the specified 4liter bottle, a glass or plastic vat having a larger capacity may be used providing the liquid level of the working solution is maintained between 915 to 1175mm above the work surface.
2) A 85 ml tinned box approximately 57mm in diameter, with gill style cover and having a capacity of 85 +/- 5ml.
3) A wide mouth funnel approximately 100mm in diameter at the mouth.
4) A clock or watch reading in minutes and seconds.
5) A mechanical shaker having a throw of 203.2 +/- 1.02mm and operating at 175 +/- 2 cycles per minute.
6) Dissolve the calcium chloride in 1.89 liters of distilled water. Cool the solution, then filter and add the glycerin and formaldehyde to the filtered solution, mix well, and dilute to 3.79 liters with distilled or dematerialized water.
7) Prepare the working calcium chloride by diluting one measuring tin full 85 +/- 5ml of the stock calcium chloride solution 3.79 liters with water. Use distilled water for the normal preparation of the working solution.

Sample preparation:   
The sand equivalent test shall be performed on soils or graded aggregate materials passing the 4.75mm sieve. All aggregates of fine-grained soil material shall be pulverized to pass the 4.75mm sieve, and all fines shall be cleaned from the particles retained on the 4.75mm sieve and included with the material passing the 4.75mm sieve. Split enough of the original sample to yield slightly more than 85ml tin measures of material passing the 4.75mm sieve. Use extreme care to obtain a truly representative portion of the original sample.

Procedure:
Siphon 101.6 +/- 2.5ml of working calcium chloride solution into the paste cylinder. Pour the prepared test sample from the measuring tin into the plastic cylinder using the funnel to avoid spillage. Tap the bottom of the cylinder sharply on the heel of the hand several times to release air bubbles and to promote thorough wetting of the sample. Allow the wetted sample to stand undisturbed for 10 minutes. At the end of the 10-minute soaking period, stopper the cylinder, then loosen the material from the bottom by partially inverting the cylinder and shaking it simultaneously. Hold the cylinder in a horizontal position and shake it vigorously in a horizontal linear motion from end to end. Shake the cylinder 90 cycles in approximately 30 seconds using a throw of 229 +/- 25mm. A cycle is defined as a complete back and front motion. To properly shake the cylinder at this speed, it will be necessary for the operator to shake with the forearms only, relaxing the body and shoulders.

Allow the cylinder and contents to stand undisturbed to 20 minutes, read the level of the top of the clay suspension. This is referred to as the ‘clay reading’. After the clay reading has been taken, the ‘sand reading’ shall be obtained by the following method:

When using the weighted foot assembly having the sand indicator on the rod of the assembly, place the assembly over the cylinder and gently lower the assembly towards the sand. Do not allow the indicator to hit the mouth of the cylinder as the assembly is being lowered. As the weighted foot comes to rest on the sand, tip the assembly toward the graduations on the cylinder until the indicator touches the inside of the cylinder. Subtract 254mm from the level indicated by the extreme top edge of the indicator and record this value as the ‘sand reading’.

Calculations:

Sand equivalent (SE) to the nearest 0.1 using the following formula:

                                                       Sand Reading
                             SE     =         -------------------------- X 100     
                                                      Clay Reading


Comments

Post a Comment

Testing method

STRIPPING VALUE OF AGGREGATES.

STRIPPING VALUE OF AGGREGATES. (IS: 6241 – 1959) INTRODUCTION: Bitumen and tar adhere well to all normal types of aggregates provided they are dry and are not exceptionally dusty. Largely the viscosity of the binder controls the process of binding. When the viscosity of the binder is high, coating of aggregates by the binder is slower. In the absence of water there is practically no adhesion problem in bituminous road construction. Two problems are observed due to the presence of water. First, if aggregate is wet and cool it is normally not possible to coat with a bituminous binder. This problem can be dealt with by removing the water film on aggregate by drying, and by increasing the mixing temperature. Second problem is stripping of coated binder from the aggregate due to the presence of water. This problem of stripping is experienced only with bituminous mixtures, which are permeable to water. Object : To determine the stripping value of aggregates by static i...
Read more

TEN PERCENT FINES VALUE.

Image
TEN PERCENT FINES VALUE. ( BS : 812 – PART – 111 ) INTRODUCTION: The ‘Ten percent fines’ value is a measure of resistance of the aggregates to the crushing. Object : To determine the ten percent value of aggregates by crushing machine apparatus. Apparatus : a) Steel cylinder with open ends, and internal diameter 152mm, square base plate, plunger having a piston of diameter 150mm, with a hole provided across the stem of the plunger so that a rod could be inserted for lifting or placing the plunger in the cylinder. b) Cylindrical measure having internal diameter of 115mm and height 180mm. c) Steel tamping rod with one rounded end, having a diameter of 16mm and length 450 to 600mm. d) Balance of capacity 3 kg with accuracy up to 1gm. e) Compressive testing machine capable of applying load of 40 tonnes, at a uniform rate of loading of 4 tonnes per minute. Procedure : The aggregate passing 14mm IS sieve and retained on 10mm IS sieve is ...
Read more

DUCTILITY TEST. ( IS : 1208 – 1978 )

DUCTILITY TEST. ( IS : 1208 – 1978 ) INTRODUCTION : In the flexible pavement construction where bitumen binders are used, it is of significant importance that the binders form ductile thin films around the aggregates. This serves as a satisfactory binder in improving the physical interlocking of the aggregates. Object : To determine the ductility of the bituminous material. Apparatus : a) Ductility machine. b) Briquette moulds. c) Knife. Procedure : The bitumen sample is melted to a temperature of 75 to 100 0 C above the approximate softening point until it is fluid. It is strained through 90 micron sieve, poured in the mould assembly and placed on a brass plate, after a solution of glycerin and dextrin is applied at all surfaces of the mould exposed to bitumen. After 30 to 40 minutes, the plate assembly along with the sample is placed in water bath maintained at 27 0 C for 30 minutes. The sample and mould assembly are removed from water bath ...
Read more