The test for the index properties of soils helps us to ascertain the behavior of soils in construction. It may include the physical and mechanical properties of soil.
In these very project carried out by me and the geologist present, we use the fill material (laterite) to test for the Atterberg limits of which we will discuss the following in this chapter
·              Liquid limit
·              Plastic limit
·              Linear shrinkage limit

Other features tested on the material collected are the
·              Compaction test
·              The C.B.R (California Bearing Ratio) test.
·              To be discussed are the aims for such test [to determine the optimum moisture content and the maximum dry density] along with its process and each conclusion.
            The liquid limit test is a test that is carried out to determine the ability of the fill material (soil) to retain or absorb water and still retain its strength.
            The test starts with the sieving of the material (soil sample) into a flat pan. Then a certain amount of water is then poured into the sieve material after which it is then mixed together with our hands for about 5-10 minutes until there is a proper mix between the water and the material. Then the material is collected into a sample bag where it is then wrapped and stored for about 24hours. Then after 24hours is achieved, the stored material is then placed on a glass board where it is remixed again this time for about 4-5 minutes after which the material is then collected and placed on the cassagranda (liquid test device) has a handle and beside the handle is the meter where the number of blows would be read from. After the material is placed on the cassagranda a spatula is used to smoothen the surface of the material. After that is done, the grove is then used to create a marginal demarcation in the middle. This would help to determine the endpoint of the attainment of the liquid limit by the material about 25 blows is usually hit in the liquid limit test.
         In measuring the (LL), if the soil strength is above 35%, then the (LL) is good. But if it’s below 10% then the (LL) is low.
            In determining this values the sample after undergoing this (LL) test is then collected in a sample can which would be measured as the  initial weight (wet sample), then it would be placed in the oven for 24hours after which  it would be then measured again as the final weight or dry sample weight.
Then we evaluate the values after the liquid limit calculation in the chart and thus deduce the O.M.C and M.D.D (optimum moisture content and maximum dry density) of the material.

The plastic limit is a feature that is measured to determine the behaviour of moulds (holes) in the soil.
            The test starts similarly with that of the liquid test where the material (soil) is filtered and collected over a pan and then water is being added and then subsequently mixed and wrapped in a sample bag to retain its moisture and this also would be kept for 24hours. After 24hours is over the damped material is collected and mixed again for about 4 – 5 minutes with a spatula on the glass board, after mixing, we use our hands to collect  the sample and then roll it gently on the glass board until a length of 3mm is attained. Then each of the 3mm sample is then placed into the measuring can where it is then measured on an electronic weighing scale as the wet sample after which it is then placed into the oven for about 24hours and then it would be removed and measured as the dry sample weight and other values would be calculated to determine the O.M.C and M.D.D.
            In measuring the (PL) of the soil material, when the (PL) is below 10%, then the (PL) is low but when it is above 40%, then the (PL) is high and these behaviour is usually observed physically with cracks after compaction (when the PL is low) but there would be no cracks when the (PL) is high.
The linear shrinkage limit test is a test that is carried out to determine the strength of the material and also to determine the reaction of the soil material in its absorption or reduction of water.
These similarly are started off by sieving the material, then water is been added into the sieved material and mixed well until damped. After which it would be wrapped and stored for about 24hours, after which it would be collected and mixed again on the glass board after which the linear shrinkage mould would then be used to collect the sample. The spatula is used to carry out and smoothen the surface of the shrinkage mould after which a meter rule/ruler is used to measure the length of the mould plus material and also it would be weighed as weight of wet sample, then it will be placed in an oven for about 24hours, after that it would be removed and also the length of the shrinkage (observable feature) will be measured and then weighed as the weight of the dry sample. Other factors would be calculated so as to obtain the O.M.C and M.D.D.

The aim of the compaction is to determine the bearing capacity of the fill material (soil) and also to ascertain the soil strength. The test starts with sieving of the material using the pan (3/4) to remove the stone particles, then we place a tray place a tray on an electronic weighing scale and weigh about 300kg of the sample which would be compacted. Then we divide the sample into 4 parts each weighing 75kg to be compacted individually, then we pour the first part of sample into a flat tray where we then mix the material with water (a measured volume of water)  that is to be compacted with 4%, 6%, 8% and 10% volume of water which would be used to obtain the M.D.D and OMC (maximum dry density and optimum moisture content).
 In deriving the volume of water to be used in the compaction test we use the format below:
Total weight of sample = X/100
Where X = volume of water
= 3000kg/100        = 30kg
Obtain the volume of 12% of water to be used for the compaction test
= 30 x 12
= 360cm (measured using a cylinder)
About 360cm of water would be used to compact about 12% of the fill material.
            After the material has been added and the mixing is done, we ensure that the entire material is well damped then we use the scoop to pick the sample and then pour it into the compaction mould and the rammer which weighs about 25kg is used to hit the 25 blows into the mould and this would be done in 3layers. These results in the formula for compaction (3/5) that is 3layers and 25blows also a tare can would be used to collect some sample. This also would be the major determinant in obtaining the O.M.C and these would be measured as the initial weight (wet sample) and also the final weight (dry sample, after being removed from the oven after 24hours).
 After the compaction of the material (in the compaction mould), the surface is then smoothen by the use of a spatula. The mould is then weighed in an electronic weighing scale. The process is repeated for the next 4 volumes of water and these is to enable us to get 2 rising point and falling point to be used in plotting the graph which would give the O.M.C and M.D.D.

            The C.B.R test is a test that is carried out to determine the strength and stability of the fill material (soil) and also the shearing resistance of the soil when a load is placed upon it, telling us it`s response and also the layering if other base materials that would be placed on the fill material.
            The process starts with the soaking of the compacted material in a compaction mould placed in a water bath for about 48hours with filter papers on both ends of the mould (top and base). Next the C.B.R machine is set up with dial gauge (used in measuring penetration) on both of the 2 gauges set about 0.0sec, then the gap between the load and the penetration pin and  the piston are set so as to accommodate the mould that would be placed inside the C.B.R machine. After the setup is done then we power on the motor and then wait till there is contact between the penetration piston/plunger and the compaction mould and these can be observed physically by the movement of the dial gauge.
            Then in taking the reading values of the penetration of the material from the 2 dial gauge we count every 0-25 revolutions of the top dial gauge to 1 revolution of the lower dial gauge. While we also read from 25-50 revolutions at the top to the lower dial gauge.

The aim of the sieve analysis is to determine the quality and durability of the soil material and the process starts with the washing of the material using sieve pan no. 75 and 2.36 after which the washed sample is then dried in the oven for about 24hrs after which the samples are then poured into the sieve pan (each with various sizes) after which we shake the pan for about 3-4mins and then each is poured into the pan and it is then weighed. Before it is being weighed the pan is first measured so as to determine the weight of the pan before any material is poured on it. A brush is used to remove any remaining particle on any of the sieve pan so as to ensure that there are no errors in calculating the results.
Mortar compressive strength test
Equipments/Materials Used: mixing machine, 2.5mm mould, scrapper, Dangote cement, water cylinder and a water bath.

Get the sample (Lafarge cement) from the delivery truck and weigh 490g, then mix with sand (1350g) and water (237ml) and place in a mixing machine for about 10minutes. After mixing you put the mortar in moulds of 2.5mm and compact using a tamping rod (25blows) , a scrapper is used to smoothen the surface and allowed to dry for 24hours. After the 24hours, you remove it from the mould and cure for 3days, 7days and 28days for it to attain its maximum strength. Then you crush using the crushing machine and the values gotten.
Note: The value gotten depends on the type of cement used.
Cement Setting Time Test
Equipments/materials used: vicant, water cylinder, vertical plug and a mould.
Collect a cement sample (Dangote cement) and weigh 650g and mix with water, after mixing you place it in a mould. Using the vertical plug placed in the vicant to check its testing value (it must be between 8-11cm, if below 8cm the water is excess and the mixture thrown away and the process repeated. But if above 11cm, water is added till it gets in range). The vertical plug is then removed and a vertical pin is placed for the vicant penetration and time of commencement recorded, the penetration is recorded at 20minutes interval till the cement sets. The time it starts setting and ends is recorded and the calculation done to get the average strength.
Grading is determined by passing a sample of aggregate through a series of sieves each of which has a smaller opening than the one preceding it. In this way all particles of approximately the same size are caught on a sieve and can be determined by weighing the amount present. Thus it can be determined whether the load is deficient perhaps in fine materials or contains too much oversize material.
The grading of concrete aggregate, particularly fine aggregate, has marked effect on the workability of the concrete. If the grading varies from load to load, the mixer operator has difficulty controlling the amount of cement and water he must add to the mix to keep the workability constant. The mixer operator should never adjust the workability by simply adding more water, since this will weaken the concrete.
To obtain the grading of the aggregate, take a weighed representative sample and pass it through a nest of sieves, beginning with the sieve having the largest openings. Make sure the sieves are well shaken to ensure that all the fine material passes through. Then weigh the amount of material retained on each sieve and report as the percentage retained on each sieve size.
Slump Test

Equipments/material used: slump cone (300mm high, 200mm diameter at bottom and 100mmdiameter at top), tamping rod (600mm long, 15mm diameter and bullet pointed), a scoop and a non-absorbent board.
Note: before starting the test all equipment must be clean and inside the slump cone moistened.
The slump test is a measure of the consistency (workability) of concrete and is also a simple means of ensuring that the concrete on the site is uniform.
Variation in water content of the concrete usually results in variable strengths. Other factors which can affect the slump are the grading and the particle shape of the aggregate and the cement content. A consistent slump usually means that the concrete is “under control”. If the result varies, it means that something else has varied, usually the water.
To make the test, the cone is placed large end down on the non-absorbant board surface and held firmly with the board pegs. The cone is then dilled in three layers (of approximately the same volume) by scooping concrete from the sample. Each layer is rodded 25times with the tamping rod (25 blows), the rod being allowed to penetrate the layer beneath. The strokes should be distributed over the surface of the layer uniformly (note: do not work the rod up and down continuously in one place). To ensure equal layers of concrete the first two layers should be 1/5 (after rodding) and ½ the cone height respectively (300mm).
After the top layer has been compacted, the surface of the concrete should be struck off level with the top of the cone and any surplus concrete removed from around the base.
The slump cone should be lifted, carefully but firmly, straight up so that the concrete is allowed to subside.
To measure the slump, place the pointer from the 300mm caliberated rod and measure the amount of subsidence.

Compressive/Crushing Test
The strength of concrete is determined by making specimens, curing them and then crushing them to determine their maximum failure. The preparation of the specimen is the most important phase of the test, for a badly prepared specimen will nearly always give a low result.
Compressive test specimens are normally with cubes of 150mm in diameter 300mm high, although other sized moulds of 100mm by 150mm cubes are also used. These different sizes and shapes will give different compressive stresses at failure even though the same concrete is used.
Cube moulds should be made of metal or plastic and should be rigid enough to hold their shape during preparation of the specimen. The mould must be clean and the inside surfaces coated very lightly with a film of oil.
To mould the specimen, a sample is collected and put into the mould as soon as possible in three layers, each layer being rodded 25times with a tamping rod or a vibrator (30mm in diameter) in two layers. After compaction, the concrete is struck off and finished with a wood float. The cover plate is then attached and the mould marked or it’s number recorded or an identification tag wired onto the mould.
The specimens should be stored for 18-24hours at a storage temperature between 130 C and 330 C and carefully stripped and the side marked with waterproof crayon or paint to show the date of casting and reference number. The concrete is then placed into a water bath or fog room where the temperature is maintained at 230 – 20 C (curing).
After 28days, the cube is removed and taken to the crushing machine where it is loaded individually and crushed. The load failure is the displayed on the machine screen and recorded or printed.
Note: tests for 3days and 7days can be can be conducted using the same concrete to test run if the 28days failure is in range

    Pile foundation is a substructure that carries and transfers the load of a structure to the bearing/ solid ground located at some depth below the ground surface. It is a load carrying and transferring system.
It is a formation that strengthens the bearing capacity of unstable and weak soil for construction purposes. The main components of the pile foundation are the pile cap and piles.

·                    To transmit a foundation load to a solid ground.
·                    To resist vertical, lateral and uplift load.

This is a long slender formation which transfers load to deeper soil or rock of high bearing capacity displacing shallow soil of low bearing capacity. It is a convenient method of foundation for works over water such as jetties or bridge piers.

    The main types of materials used for piling bare wood, steel and concrete. Piles made from these materials are driven, drilled or jacked into the ground and connected to the pile caps.
·        Timber Piles
·        Concrete Piles
·        Steel Piles
·        Composite  Piles
DRIVEN PILES: Are considered to be displacement piles, in the process of driving the piles into the ground, the soil is moved radially as the pile shaft enters the ground. There may also be a component of movement of the soil in the vertical direction.
Driven piles with the pile driver (crane)
Bored piles (Replacement piles) - Are generally considered to be non-displacement piles; a void is formed by boring or excavation before pile is produced. Piles can be produced by casting concrete in the void.
Some soils such as stiff clays are particularly amenable to the formation of piles in this way, since the borehole walls do not require temporary support except cloth to the ground surface. In unstable ground, such as gravel, the ground requires temporary support from casting or bentonite slurry.
Prefabricated concrete piles (reinforced) and pre-stressed concrete piles
·        Do not corrode or rot
·        Are easy to splice. Relatively inexpensive.
·        The quality of the concrete can be checked before driving.
·        Stable in squeezing ground, for example, soft clays, silts, and peats pile material can be inspected before piling.

The first step is to run a geophysical survey on the proposed site (after reconnaissance). Soil investigation and geotechnical survey is carried out to check the soil profile and lithology of the ground before boring of the ground commences using the designed rig (we have 450mm, 600mm, 800mm,1000mm and 1200mm in diameter of rigs).
After the various survey was carried out, the ground surface was found to have clayey and silty materials followed by weathered rocks and then fresh rocks which served as base rock for the pile foundation. The boring is done to come in contact with the base rock (fresh rock) at varying depths based on when in contact with the base rock, after that a temporal casing is put to make the ground stable to avoid the hole from being filled with loose particles and possible collapse, a re-enforcement (rods woven like a basket) is then placed in the bored hole with regards to the depth. A tremie pipe is placed on the hole (serves as funnel for proper casting) before casting is been done immediately using a mobile concrete mixer to avoid the hole from being filled with lose particles or rain water, the process is repeated for all the bored hole.
Note: at times during drilling, the rig might hit an aquifer or wet soil leading to seepage and the hole filled with fluids which will lead to collapse or failure, also the casting must be done properly to avoid the concrete mixing with loose particles and clays which will lead to weakening of the pile and possible failure. If properly casted, the clays (montmorrilorite) will be pushed to the surface.
The pile cap is done next after about 2meters of the casted pile is exposed and re-enforced with rods of sizes ranging from 8mm to 35mm. The pile cap then forms the foundation for the abutment to be raised. After the abutment is raised at both ends, columns are then raised to support the beam which is placed on the abutments for it to rest on it.

   This is a structure or the part of a structure which bears the load or pressure of an arch. It is a structure that supports the end of a bridge.
   It anchors the cables of a suspension bridge.
This is a structure that retains the soil and water behind it, hence, it bears mostly sideways load. It must resist overturning, sliding as well as any vertical load.
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