TYPES OF AGGREGATE ON THE BASIS OF TEXTURE

TYPES OF AGGREGATE ON THE BASIS OF TEXTURE:

On the basis of surface texture, aggregates are divided into two main types. 

i)                  SMOOTH aggregate:

            It is a type of aggregate having smooth in texture and touch. It has maximum number of rounded material.

ii)               ROUGH aggregate:

           It is a type of aggregate having rough in texture and touch. It has maximum no of flaky and irregular type of material.

TYPES OF AGGREGATE ON THE BASIS OF GRADATION

TYPES OF AGGREGATE ON THE BASIS OF GRADATION

Aggregates type on the basis of gradation have further four types.

i)                  POORLY GRADED aggregate:

            It is a type of aggregate which is poor in ratios. Their graph is not regular.

ii)               WELL GRADED aggregate:

            It is a type of aggregate which is good ratios of their aggregate constituent. It has straight line with some angle in graph.

iii)            UNIFORMLY GRADED aggregate:

            It is a type of aggregate having uniform ratios of their constituent. It has a uniform vertical in graph.

iv)            GAP GRADED aggregate:

            It is a type of aggregate having vertical line with some angle, but there are some places which are missing and that provide horizontal line.

Types of Aggregates on the Basis of Moisture Content

TYPE of Aggregates ON THE BASIS OF MOISTURE:     

                       Types of aggregate on the basis of moisture have four following types.

i)                  DRY  aggregate:

           It is a type of aggregate having no water in it.

It has low weight, and having original weight of the material.

ii)               OVEN DRY aggregate:

           When an aggregate is subjected to heat in an oven for 100◦C  for about 1 hour. Then aggregate is called oven dry.

iii)            SATURATED SURFACE DRY (SSD) aggregate:

            It is a type of aggregate having about only their surface is dry, but internally it contains some water.

 It has less in weight from wet aggregate but more in weight from oven dry and dry aggregate.

iv)            WET aggregate:

           

             When a saturated surface dry aggregate is place in water for a long period of time, then it is called wet aggregate.

Types of Aggregate on the Basis of Shape

TYPES of Aggregate ON THE BASIS OF SHAPE

              There are many types on the basis of shape of concrete.

i)                SPHERICAL aggregate:

              It is a type of concrete having spherical in shape.

This type is used in semi circular arches, bridges and circular beams.

ii)             ELONGATED aggregate:

              It is a type of concrete having cylindrical in shape.

This is used in mega projects design and for beauty purposes.

iii)            FLAKY aggregates:

              It is a type of aggregate having irregular type of structure.

It has sharp edges and a bit elongated.

iv)            ROUNDED aggregates:

             It is the type of aggregate having rounded in shape. 

It is most simple type of aggregate.

Aggregates and Types of Aggreagtes

 There are many civil engineering materials.

          Aggregate is the combination of different civil engineering materials i.e. sand, stones and cements.

         Anywhere in the world any aggregate is made by the mixture of different materials, but these mixtures are mixed in such a way that they are mixed in proper proportion. Aggregate demand is getting higher and higher around the world.

TYPES:

          There are many types of aggregates in the language of civil engineering language. It is distributed in such a way that there types can provided ease in  the site work of engineering because of ease in selecting ratios of aggregates and their notation of the type for proper work.

MAIN TYPES OF AGGREGATE:

             There are two types of aggregates which are the main division.

i)                  Fine aggregates.

ii)               Coarse aggregates.

FINE AGGREGATES:

            It is a type of aggregate which are consists of sand and cements.

COARSE AGGREGATES:

            It is a type of aggregate which contains of large and small size stones, sand and cements.

OTHER TYPES OF AGGREGATE

1. TYPES ON THE BASIS OF SHAPE
2. TYPE ON THE BASIS OF MOISTURE Content
3. TYPES OF AGGREGATE ON THE BASIS OF GRADATION
4. TYPES OF AGGREGATE ON THE BASIS OF TEXTURE

DEFECTS OF TIMBER

DEFECTS OF TIMBER:

                                           Any disturbance in the quality that affects the strength, workability, durability, utility, appearance and decay etc is said to be the defects in timber.

Growth Related Defects:

1. Shakes:

  Change in shape of trunk or cracks in timber are called shakes. It is of three types.

·         Star shakes.

·         Hearth shakes.

·         Cap.

2. Knots:

                  A knot is the base of branch that is attached with the wood of tree trunk or to a large branch.

3. Rind galls:

                    Swelling due to injuries inflected to the wood in its younger age.

4.     Twisted fibers:

                      Wood is twisted due to strong winds during the early stages of its growth.

5.     Upsets:

                  Change in wood direction in young age by to fast blowing winds.

DEFECTS AFTER FELLING:

1. Wane:

                 The roundness of timber surface without bark.

2. Twists:

                Ends of the trunk are twisted in opposite directions.

3. Bow:

                Curve made along the face of timber due to shrinkage.

4. Cupping:

                     Curve formed across the width of trunk.

5. Checks: -

During felling of tree from stem internal stresses causes checks.

6. Splits:

Splits are the lengthwise separation occurs due to the reason of inappropriate handling of drawing stresses or forces.

Types of Timber

Types of Timber:

                       According to its botanical origin wood is classified into two kinds:

Soft wood:

                 Soft wood is obtained from Gymnosperms. Soft wood from coniferous trees like pine etc, , and are generally lighter and  simple in structure.

Hard wood:

                 Hard wood is produced from Angynosperm, known as Dicotyledons. They contain broad leaf trees and are strong, harder and more complex.

CHARACTERISTICS OF SOFT WOOD:

·         Light in color

·         Fast or rapid  growth

·         Low weight

·         Low density

·         Distinct annual rings

·         Hearth wood and Sap wood cannot be separated or distinguished

·         Strength is strong along the grains

·         Conversion is easy

·         Resonance material usually exist in pores

 Examples are chirr, fir and other conifers.

CHARACTERISTICS OF HARDWOOD:

·          Dark in color

·         Slow or gradual  growth

·         Heavier weight

·         High density

·         Indistinct annual rings

·         Hearth wood and Sap wood can be separated or distinguished

·         Strength is strong along and across the grains

·         Conversion is difficult

Examples are sheshum, oak, teak and other desidous trees.

Timber and Parts of Timber

TIMBER:

It is defined as:

      “TIMBER IS THE MATERIAL OR PRODUCT OBTAINED WHEN CUT AND MACHINED FROM THE TREES”

PARTS OF Timber:

 Generally there are three parts of a tree i.e.;

1.      Roots

2.      Stem

3.      Branches

PARTS OF TRUNK:

Trunk is said to be the main woody stem of a Tree.

Trunk parts are:

1. Bark:

      The protected outside cover of the trunk located outside is called bark.

2. Annual Rings:

                         These are also called the growth rings of the tree. These are actually the marks or positions show the yearly growth of the trunk.

3. Pith:

            The central or inner part of the trunk.

4. Hearth Wood:

              The wood which is responsible for surrounding the pore of the trunk.  Usually dark in color and have little or no sap.

5. Sap Wood:

                Most recent annual rings formed in this portion of the trunk. It is about 20-50% of the total radius of trunk.

6. Cambium Layer:

                         Development or growth area of the trunk is called cambium layer.

7. Xylem:

            Transportation of water is done through this part of wood/trunk.

8. Phyleum:

                   The inner part of the bark responsible for the transports organic nutrients to the wood, in case of trees it is Sucrose.

Timber and Parts of Timber

Types of rocks

Rocks:-

When the different minerals combine occurring naturally it forms the rock. The rock is formed by the composition of same or different minerals occurring naturally.

Types of rock:-

The rocks are divided into three main categories depend upon their composition.

• ·         Igneous rock
• ·         Metamorphic rock
• ·         Sedimentary rock
• 
  
• These rocks are defined one by one as under:-

1.     Igneous rock:-

When ever there is some volcanic activity or volcanic eruption inside or outside the earth they form the rock, this rock is called as igneous rock. The igneous rocks are formed when the volcanic eruption or activity takes place.

They may be classified into two types depending upon their composition. These types are defined as under:-

·        Intrusive igneous rock:-

When ever there is volcanic activity or eruption and when this activity cools inside the earth or its own place the resulting product forms the rock which is named as intrusive igneous rock. As its name shows that “intrusive means that inside” so here it means inside the earth. The intrusive igneous rocks formed when the magma settle and cools inside the earth or its own place.

·        Extrusive igneous rock:-

When the volcanic activity takes place in some area and after some period of time this volcanic activity comes outside the earth where it cools and settle. This process led to the formation of extrusive igneous rock. As its name shows that (extrusive means outside) here we means that outside the earth surface. The extrusive rocks are formed when lava from the earth comes outside and cools, settle on the earth surface.

2.     Metamorphic rock:-

When ever the any rock (Sedimentary rock,Igneous rock) are under the action or influence of “heat” and “pressure” they form the rock this rock is called as “Metamorphic rock”. The metamorphic rock is formed by the variation or change in heat and pressure in sedimentary rock or igneous rock.

Types:-

They are sub divided into three different classes:-

·        Foliated Metamorphic rock:-

These are those rocks or the type of metamorphic rock by seeing them through the eye one can easily see the parallel prominent layers. Foliated metamorphic rocks are those which have layers which are parallel and prominent.

·        Non- Foliated Metamorphic rock:-

This is the type of metamorphic rock that one can easily see that the layers which are not parallel and in some cases not prominent.Non- foliated metamorphic rock are those which have the layers, and these layers are not parallel.

·        Cataclastic Metamorphic rock:-

When ever some small pieces of minerals are combine or join together they form cataclastic metamorphic rock. Cataclastic metamorphic rock consists of composed small broken up minerals.

3.     Sedimentary rock:-

When ever the minerals moves or transported from one place to another they form the rock this rock is called sedimentary rock.Sedimentary rock is formed from the transportation of sediments from one place to another by the action of wind, glacier or river etc.

Agents of transportation:-

There are three main agents of transportation of sediments from one place to another are as under:-

·         River

·         Wind or air

·         Glacier or ice

Rock Cycle:-

This whole process is represented by this diagram:-

Planning in Civil Engineering Projects

Planning and management are the basis of a civil engineer while construction of any structure. Project management is the way to apply your knowledge and skills to project activities as per the requirements and need of the stakeholder. The main purpose of planning is to give a path that helps us to predict which resources are needed on time for its completion. After this, policies are made that makes sure proper management of these resources .This ensures that the project will be completed in required budget and delivered on time. In this modern era, technological advancements have lead mankind to design software for the ease of engineers for planning such as primavera, MS Office etc. In developing countries for construction no much heed is paid to the phase of management and planning, therefore, completion of project within time and budget is still a dream.

Planning in civil engineering projects is about planning your manpower, money and machinery. It is for identification of goals and opportunities.

It gives a direction to an engineer. A civil engineer who is an expert in the planning field can also plan stuff related to other engineering fields. This is because when you are planning a building, you also take mechanical and electrical activity in account. This makes a planning civil engineer lead the project and the company. It is the sole duty of a planning civil engineer to make sure smooth run if everything until the project is finished. His duty is to make sure the project is completed in time. . It is said that in terms of success, if someone has 10 years of experience of any technical specialty like structure, then he will be equivalent to a person for management having 5 years of experience.

In planning, you have a strong coordination with the site staff and senior management for you have to take in account that in how many days you want that work to be done. Accordingly, manpower is allotted to site staff and then its responsibility of planning engineer to tackle the technical issues that may be present in drawings as soon as possible. Planning engineers have to work at every tiny detail of the work handed over to them. Alternative plans must be made in advance, if uncertainty sneaks in at any stage.

Factors which cannot be controlled, can lead to the failure of plans so it is a major priority of a planning engineer to provide some cushions that are in their plan to compensate the time loss is and make their plan realistic and consequently successful. Important phase of planning is monitoring while execution of plan. Planning helps us to minimize uncertainties such as unavailability of labor, equipment, work machines etc and through planning we may have backups which can lead us to give solutions to our sudden occurring problems. If the work is done on the basis of planning and without any hindrance, we surely are on the paths of success.

If the pace of work is not according to plan then planning department should point out the reasons to make your plan successful and rectification of that reasons is necessitated.

Bamboo as a Reinforcement in Concrete

In a defense presentation of undergraduate students I came across an interesting project of final year students. It is a good step towards planning in civil engineering projects. They used bamboo as a reinforcement in concrete and compared its results with an ordinary reinforced concrete. Bamboo when properly seasoned gives sufficient stiffness and strength can be used as a roof shed in poor people lodgings. It grows 3.2 cm every month and can be available in any size and diameter as required. The students incorporated bamboo in concrete and conducted compressive strength, tensile strength, durability test and pull out test on the samples. Results showed adequate strength for the samples and it was concluded that bamboo is much more durable then steel although not much strengthened then steel reinforced concrete but can be used for single story construction and can be very economical for providing shelter to poor people in Pakistan.

Read More about Bamboo Reinforced Concrete

Itaipu Dam Brazil Hydro energy

The Itaipu Dam is a hydroelectric power plant which is currently the largest in the world. Built from 1975 to 1991 by Brazil and Paraguay on the Parana River. It took 16 years to build this series of dams whose length totals 7,744 meters. It used 15 times more concrete than the Channel Tunnel. The name "Itaipu" was taken from an isle that existed near the construction site. Itaipu, from the Guarani language, means "singing stones". The Itaipú dam is one of the Seven Wonders of the Modern World, according to a worldwide survey conducted by the American Society of civil Engineers (ASCE) in 1995 and is producing 14750 MW.

Keywords: Itaipu Dam, Itaipu Brazil, hydro energy,

Typical Drip Irrigation System Layout !!!

RQD Index in Tunneling

RQD Index in Tunneling

As noted previously , the RQD concept was developed for tunneling, firstly as an aid in siting tunnels and shafts in the best ground conditions possible, and secondly as a guide in assessing tunneling conditions and selecting the initial supports. Papers published in the 1969- 1970 period , presented tables relating tunnel support and RQD based on the University of Illinois sponsored research efforts. Cecil  published in 1970 his work on correlation of RQD with rock bolt-shotcrete support as used in Scandinavia.
rqd rock

Merritt in 1972 made use of his recent experience and the works cited above to present an improved version based on 58 cases which included tunnel widths ranging from 2 m (6 ft) to 20 m (60 ft). He compared the support criteria as shown by his system as a function of tunnel width and RQD with those proposed by Peck  and Cecil . Table I is based on Merrill's Fig. 3 and has been selected for a 6-m (20-ft)-wide tunnel, a common tunnel size for pressure tunnels and a single-t rack rapid trans it tunnel.

Merritt  points out problems associated with any attempt to precisely correlate rock quality with the tunnel support actually used:

RQD Index in Tunneling

rqd rock

Unfortunately, the selection of tunnel support docs not always depend upon the actual rock conditions.

The method preferred by the contractor may be based on a favorable unit price for steel sets as opposed

to bolts, or the lack of adequate equipment for the rapid placement of either sets or bolts. The preference

for set in the first place may be based on an overcautious safety program . .. although no method for

predicting tunnel support criteria is foolproof, the writer believes this system can be of great value for

design and estimating support purposes. The RQD method of core analysis is simple, inexpensive, and

reproducible and it has an advantage over joint frequency, for example, in that joints can only be counted

in recovered core . rqd rock .. The RQD support criteria system has limitations in areas where the joints contain

thin clay fillings .. .

rqd rock

Rock Quality designation (RQD)

Definition

The Rock Quality designation (RQD) index has been used for over 20 years as an index of rock quality. It measures the percentage of "good" rock within a borehole. It was developed by the senior author originally as a means of qualitatively describing whether a rock mass provided favorable tunneling conditions. It is now used as a standard parameter in drill core logging and forms a basic element of several rock mass classification systems [1,2]. Perhaps its greatest value is its simplicity , which allows for the delineation of zones of poor quality rock that could adversely affect engineering structures.

This article presents the background for the development of the RQD, the recommended procedure
for measuring RQD, and examples of its use in practice.
rqd rock

Background

rqd rock
In 1963 a paper was published by Deere [3 ] entitled "Technical Description of Rock Cores for Engineering Purposes" in the first volume of Felsmeclwnik and lngenieurgeologie (Rock Mechanics and Engineering Geology). This would have been an excellent international forum for introducing the RQD concept but it was not included because it had not as yet been devised. It was in the following year that the senior author developed the RQD concept to assist in the siting and the decision of tunnels and large caverns in granite at the Nevada Test Site. In 1965 it was extended to the design of highway tunnels in massive quartzite, gneiss. and schist in North Carolina .
Because of its success in these early applications to tunnels as actually designed and built, the RQD concept appeared worthy of a continuing research effort. It was at the University of Illinois that the RQD concept was first applied to a wider range of rock engineering problems.
In 1967 Deere and his colleagues at the University of Illinois [4] presented for the first time in published form the RQD concept of rock quality logging together with some correlations with velocity indexes, fracture frequency, and in situ modulus values. The method or measuring RQD was given as well as a brief discussion of some of the difficulties involved in determining it.
The published work that introduced RQD to an international audience, and that no doubt was responsible for its rapid growth in use in many countries, was Rock Mechanics in Engineering Practice ( 1968) [5]. This contained chapters by Deere [6] and by Hendron [7] in which the RQD concept and applications were discussed.
Research continued at the University of Illinois on tunneling and the application of the RQD index under the sponsorship of the U.S . Air Force and the U.S. Department of Transportation. This research lead to several publications in the late 1960's and early 1970's [8-12]. During the 1970's the RQD index began to be used as a basic parameter in several classification systems for
rock masses (Bieniawski [I ,13], Barton ct al[2]).
rqd rock

References

[I] Bieniawski, 7 .. T ., " Engineering Classification of Jointed Rock Masses . '· Transactions of the South African Institute of Civil Engineers, Vol. 15, 1973, pp. 335- 344.
[2] Barton, N . . Lien, R., and Lunde, J., " Engineering Classification of Rock Masses for the Design of
Tunnel Support," Rock Mechanics. Vol. 6 , 1974 , pp. 1!!9-2.16.
[3] Deere, D. U., " Technical Description of Rock Cores for Engineering Purposes.' " Felsmachanik and
 lngenieurgeologie (Rock Mechanics and Engineering Geology). Vol. I, No. I, 1963. pp. 16- 22.
[4] Deere , D. U. , Hendro n, A. J ., Jr. , Patton, r. D. , and Cording . E. J .. " Design of Surface and Near Surface Construction in Rock,' ' in Failure: and llreokogc of flock. C. Pairhurst, Ed ., Society of Mining Engineers of AIMF. , New York , 1967. pp. 237- 302.