Stones

INTRODUCTION OF STONES

Rock and stones is a naturally occurring solid aggregates of minerals and mineraloids in term of geology. Rock has variety uses in building such as blocks in masonry wall, slabs in floorings, aggregates in concrete and terrazzo in floor finishes. There are two types of stones artificial stones and natural stones.

ARTIFICIAL STONES

Artificial stones also known as engineered stone. Artificial stones are usually use with Portland cement with low water ratio. There are two types of artificial stones used in manufacturing such as calcareous stone materials and siliceous materials. The nature, colour and quality of aggregates will determine the aesthetic appearances of artificial stones. Artificial stones widely use in outdoor and indoor floorings, outside claddings, internal facings due to its wide dimensional range and good looking appearance.

NATURAL STONES

Igneous rock formed from the cooling and solidification of magma and lava. Igneous rocks are geologically important because they gives information about composition of mantle. Igneous rock consists of batholiths, laccoliths, sills and dikes. Granite is the main igneous rock use in building construction. Granite has a hard and durable and able to withstand knocks and abrasion. Besides, granite does not carry out chemical reaction with other materials. Granite used as a damp-proof courses or bases in construction area.

Sedimentary stones is formed from by broken action of wind, water or ice to the older stone. Some of the sedimentary stones formed by the accumulation of organic materials. The main example of sedimentary stones are limestone and sand stone. Lime stone consists of calcium carbonate and mixture of magnesium carbonate. They have variety colours of calcium carbonate. Limestone are soluble in water due to they containing carbon dioxide.  Sandstones is make up of fine quarts with feldspar and bound together by cement. There are 3 types of sandstones siliceous sandstones, calcareous sandstones, and dolomite.

Make of natural stones

METAMORPHIC ROCK

MARBLE

Marble is form from the recrystallization process. Marble form naturally from limestone with heat and pressure over years in earth's crust. Marble is very hard and compact. Chemically, marble consists of calcite, dolomite and serpentine minerals. Marble has high value for its beauty, strength and good resistance to fire and erosion. Ancient Iranian and Greek were a very good user of marble in building. Large blocks of colored marble are used for columns, floors, and other parts of buildings. Smaller pieces of marble are crushed or finely ground and used as abrasives in soaps and other such products. Crushed or ground marble is also used in paving roads and in manufacturing roofing.
Marbles show variety of textures on account of existing minerals & re-crystallization patterns. Texture depends upon form, size, uniformity of grain arrangements. Marbles can be classified on the basis of the following factors :-

Calcite Marble - Mostly CaCo₃; MgCo₃<0.50%
Dolomite Marble - Having > 40% MgCo₃
Magnesium Marble - MgCo₃ between 5 to 40%
Serpentine Marble - remobilised marble due to the effect of Thermodynamic metamorphic wherein serpentine is prominent
Onyx Marble - Lime carbonate deposition on account of cold water solution activity

Impurities in Marble

Impurities in Marble

The following are the major mineral impurities in marble:

• Quartz
• Tremolite Actinolite
• Chert
• Garnet
• Biotite
• Muscovite
• Microline
• Talc
• Fosterite

The following are the major chemical impurities in marble:

• SiO₂
• Fe₂O₃
• 2Fe₂O₃
• 3H₂O
• Limonite
• Manganese
• Al₂O₃
• FeS₂(pyrite)

SLATE

Slate consists of quarts, muscovite, illite, biotite, chlorite, hematite, pyrite, apatite, graphite, kaolin, magnetite, tourmaline, zircon and feldspar. Slate can be used as material to make roof. Slate has a low water absorption index of less than 0.4%. This advantageous make slate resistant to frost damage and breakage due to freezing. Slate also use as interior and exterior flooring system. Chemical sealants often used on the slate tiles to increase its durability, appearance, stain resistance, and reduce of surface smoothness. Slate also is a good electrical insulator and fireproof and it is used as electric switchboards and relay controls for large electric motors. It also used as billiard table tops in laboratory due to its thermal stability and chemical inertness.

Blocks

Intoduction of Blocks

 Bricks = Blocks?

Blocks are larger than bricks. For sure it has a larger mass than brick also. So a block usually requires both hands to lift it up for laying. However blocks are larger, they also can laid more quickly than bricks, but the bigger size also means less versatility in laying especially when building up ends or corners and also laying to curves. Generally blocks are intended to be plastered.

There have two types of blocks:

1.      Clay blocks

2.      Concrete blocks

Between the two, concrete blocks are more widely used for construction building. Because Concrete brick is typically less expensive than clay brick.

Clay blocks

Clay is a block that is a light-blue/gray recolors of the Sand texture. Block usually can be found below water, but is sometimes found exposed in, around or under sand.

Properties

Concrete blocks (also known as concrete masonry units or CMUs) have a high important of properties: high structural capacity, resistance to fire, resistance to water, variety of aesthetic possibilities and insulating and acoustical advantages.

Strength

Clay blocks are available to minimum average compressive strength:

Non-loadbearing walls/partitions>1.4 N/mm²

Facing and common blocks      >2.8 N/mm²

Blocks for loadbearing walls     > 2.8 N/mm²

Concrete Blocks

In the United States, a concrete masonry unit (CMU) – also called concrete block, cement block, and foundation block is a large rectangular brick used in construction. Concrete blocks are made from cast concrete. Most concrete blocks have one or more hollow cavities, and their sides may be cast smooth or with a design. Lightweight blocks can also be produced using aerated concrete.

Size

Blocks come in many sizes. In the US, with an R-Value of 1.11 the most common nominal size is 16×8×8 in (410×200×200 mm); the actual size is usually about 3⁄8 in (9.5 mm) smaller to allow for mortar joints. In Ireland and the UK, blocks are usually 440×215×100 mm (17×8.5×3.9 in) excluding mortar joints. In New Zealand, blocks are usually 390×190×190 mm (15×7.5×7.5 in) excluding mortar joints.

Properties

Concrete masonry can be used as a structural element. Reinforcement bars can be used both vertically and horizontally inside the CMU to strengthen the wall and results in better structural performance. The compressive strength of concrete masonry units and masonry walls varies from approximately 1,000 psi (7 MPa) to 5,000 psi (34 MPa) based on the type of concrete used to manufacture the unit, stacking orientation, the type of mortar used to build the wall, and other factors.

Strength

The minimum crushing strength of concrete blocks are given below:

	Concrete density¹ Kg/mm³	Strength N/mm²
Dense aggregate	1500-2000	2.8-3.5
Lightweight aggregate	700-1500	2.8-10.5
Autoclaved aerated	400-900	2.8-7.0

¹Weight of block divided by overall volume.

Greener. Faster. Better.

ECO-Block is simpler and easier to install than wood-frame methods. It's faster, taking less time with fewer people. And it’s better, because ECO-Block buildings are vastly more energy-efficient.

-Stronger. – Resistant to fire, moisture and mold.

Greener

-Energy savings generated by an ECO-Block building are up to 50% and HVAC tonnage requirements reduced by as much as 30%. You can save on utility and maintenance costs. ECO-Block buildings stand strong against the wind and can have a four hour fire resistance rating.

Faster

-The ECO-Block system gets the job done faster. It’s taking less time to complete work with fewer workers. ECO-Block is easier to ship and handle than other fixed-block ICFs so it can save on transportation cost and delivery time.

-ECO-Block system is easy to learn, requiring less time for training.

l  Install window and door openings fast.

l  Train in less time with our easy-to-understand, integrated system.

l  Assemble walls of any size quickly with easy-to-snap-in connectors.

Better

-This state-of-the-art method of construction is also the simplest.

l  Build from the footing to the roofline, using one crew, one system.

l  Form walls 4” thick and greater in any configuration.

l  Create any shape or contour your design calls for.

l  Apply any exterior or interior finish.

ECO-Block, the Greener, Faster, Better way to build in the 21st century. 

Eco-Block Projects Slideshow

Bricks

BRICKS

What is bricks? 

Bricks refer to a small units of building material, often made from fired clay and secured with mortar, a bonding agent comprising of cement, sand, and water. Long a popular material, brick retains heat, with-stands corrosion, and resists fire. Because each unit is small—usually four inches wide and twice as long, brick is an ideal material for structures in confined spaces, as well as for curved designs. Moreover, with minimal upkeep, brick buildings generally last a long time.

There are various types of bricks used in masonry and have different roles

lets look at types of bricks~

TYPES OF BRICKS

Stock Bricks       

•  Traditional type of brick with a slightly irregular shape made by using a mechanized moulding process known as soft mud moulding.  
• A wide range of colours is available.

• This type of brick is currently one of the most popular. 

Engineering Bricks

 

• Used for their performance characteristics rather than their appearance

•  Most suited for ground works, manholes and sewers, retaining walls and other situations where strength and resistance to frost attack and water are the most important factor.

Fletton Bricks

• Made from deposits of Oxford clay

• Available in a wide range of colours and textures, and are particularly popular for matching existing brickwork.

Handmade Bricks

• Literally made by hand by skilled craftsmen throwing clay into moulds.

• Each brick is unique and they have a pleasing and distinctive appearance with a creased face. 

How was Handmade Bricks produced ? Well, check this video :)

Re-Pressed Bricks

• It is wirecut bricks which are re-pressed to create a solid brick with very precise size tolerances and distinctive surface texture.

• Known as the 'Jacobean', this range is unique to Butterley and is a high quality product that can be used effectively in housing.

 

Properties of Bricks

Clay Bricks

Strength

-high compressive strength, fired to sufficiency high temperature can withstand compressive strength.

Moisture movement

-reversible: Reversible moisture movement is less than calcium silicate bricks and concrete bricks.

-irreversible: Irreversible moisture movement is high which may amount to between 0.1 to 0.2 percent due to absorption of moisture from the atmosphere.

Durability

-Generally well-burnt clay bricks are extremely durable.

-Durability of bricks depends on: the amount of soluble salts present in the bricks and the firing temperature.

Fire resistance

-A 100mm thick clay brickwork with 12.5mm thick plastering can provide a fire resistance of 2 hours and a 200mm thick similar wall non-plastered can give a maximum fire rating of 6 hours.

Clay brick making process

(Skip to 2.07min & reduce your volume if the music is to loud) Enjoy the video~

Calcium Silicate Bricks

Strength

-strength is more uniform and comparable to clay bricks.

-cannot achieve the extremely high strength of engineering clay bricks.

Moisture movement

-Reversible moisture movement is greater than clay bricks but lower than concrete bricks.

Durability

-Calcium silicate bricks have satisfactory durability.

Fire resistance

-Fire resistance is good but calcium silicate brickwork need to be thicker to achieve 3 and 4 hours fire resistance.

Concrete Bricks

Strength

-harder, more difficult to cut.

-less pleasant to handle than clay and calcium silica bricks.

Moisture Movement

-Reversible moisture movement varies considerably and is greater than clay and calcium silicate bricks.

Do you know how to build a brick wall? 
Actually it is very simple. You just need to follow the step.
Well lets look at this video and you will know how to make it yourself.

Concrete

Introduction

What is ''Concrete''?

              Recyclable          

Strong   

Plentiful

   Science

 Versatile

      Everywhere

 Natural

         Inexpensive

       

        It is the material that widely used in construction field such as domestic, commercial, recreational, rural and education. There are variety of concrete such as reinforced concrete, pre-stressed concrete, and mass concrete. 

Most of the materials that use in the construction site are make out of concrete.

So What is concrete huh? 


Concrete is the mixture of cement, water, and aggregates. There are 2 types of aggregates have been used such as coarse aggregates and fine aggregates. 

           Both aggregates provide a different workability and compressive strength to the concrete. Example of coarse aggregates are limestone and granite while the fine aggregates is sand. Admixtures are also added to the concrete to change it properties to shorter the time concrete take to harden and improve its workability. Hydration is a chemical process carry by water to solid the mixture of concrete by bonding the component together. Concrete has a high compressive strength and lower tensile strength. So reinforcement is added to the concrete to increase the tensile strength of the concrete.

Concrete structure

Composition of concrete

Cement

Cement is the basic ingredient of the concrete. Calcium oxide and silicon dioxide is the most important ingredients in manufacturing cement. Portland cement is the mixture of calcium oxide, silicon and aluminium. Cement powder mixed with water to form a paste. Paste acts like glue to bond the aggregates together.

Cement

Now are you confused? 
Is it Concrete = Cement ?
let's us look at the video below⇊⇊⇊⇊

 
Now let's us look at another video showing manufacturing process for cement step by step.

WATER

Water is the components that carry out hydration to bond all the other materials together to form concrete. Different types of water will produce different types of concrete. Impure water can cause problems when setting and premature failure of structure. Excessive water will produce concrete with higher slump while less water will improve the strength and durable of the concrete. 

Equation

 C₃S + H → C-S-H + CH

 Ca₃SiO₅ + H₂O → (CaO)·(SiO₂)·(H₂O)(gel) + Ca(OH)₂

 2Ca₃SiO₅ + 7H₂O → 3(CaO)·2(SiO₂)·4(H₂O)(gel) + 3Ca(OH)₂

Cement mix with the water

What is Hydration?

Hydration is the chemical reaction between cement and water that binds the cement, water and aggregate into concrete. The strength of the finished concrete depends on proper and sufficient hydration. 
So here is the video talking bout Hydration of cement. 

AGGREGATES

 There are two basic types of aggregates, coarse aggregates and fine aggregates. Coarse aggregates mostly made up of crushed rock and gravel while fine aggregates made up of sand. Aggregates that have been chosen must be strong and hard. Crumble or flakey rock should be avoided. Aggregates chosen must chemically inactive to prevent reaction between cement and aggregates. Clean the aggregates before mix them with concrete to prevent the dirt weaken the bond between paste and aggregates. Cohesiveness of the concrete is affected by the aggregate grading. Well-graded aggregates give a more cohesive mix, too much coarse aggregate gives a boney mix.

Fine aggregates

Coarse aggregates

Mix aggregates

REINFORCEMENT

We all know that concrete is strong in compression force due to the aggregate efficiently carries the compression load. It is weak in tension stress and reinforcement is added inside concrete to withstand the tensile force.

ADMIXTURES

Materials that added to the concrete to alter the original properties of the concrete. There are 5 types of admixtures such as plasticisers, pigments, accelerators, retarders, and air entraining agents.  CaCl₂, Ca(NO₃)₂ andNaNO₃ is the accelerators that speed up the hydration process. However excessive use of chlorides may cause corrosion in the reinforcing. Sugar, sucrose, sodium gluconate, glucose and tartaric acid which are retarders to slow down the hydration process when concrete are used in large or difficult pour, hot weather, or long distances delivery. Air entraining agents controlling the quantity of air between the concrete to prevent honeycomb. Pigments is a colour agent which give a colour to the concrete. So the concrete can be more attractive.  Plasticisers increase the workability of the concrete by reducing the water inside the concrete. 

Concrete Admixtures

Concrete production

The processes of concrete production are from hand tools to heavy industry and probably used of high technology advanced. Portland cement and water rapidly form a gel, formed of chains of crystals when they mixed together. The fluid gel aiding by improving workability through react over the time. Besides, the chains of crystals join and form a rigid structure, gluing the aggregate particles. Most of the cement reacts with the residual water that mean hydration during curing.

Mixing Concrete

     For a production of uniform, high quality concrete, mixing of concrete is essential. And equipment and methods should be capable to contain the largest amount of mixing concrete materials. In order to increase the compressive strength, the mixing of cement and water into the paste is needed before combining these materials with aggregates. The paste is mixed in high-speed. The cement paste premix may include admixtures such as accelerators or retarders, superplasticizers, pigments, or silica fume. A plasticizer or a superplasticizer is then added to the activated mixture, which can later be mixed with aggregates in a conventional concrete mixer.

 Workability

Workability is the ability of a fresh (plastic) concrete mix to fill the form/mold properly with the desired work (vibration) and without reducing the concrete's quality and depends on water content, aggregate(shape or size), cementitious content and age(level of hydration). Concrete workability will increase by raising the water content or adding chemical admixtures. Concrete slump test can be measured the workability. Slump can be increased by addition of chemical admixtures without changing the water-cement ratio. After mixing, concrete is a fluid and can be pumped to the location where needed.

For workability, it have 4 test which are slump test, compacting factor test, vebe test and flow table test.

Slump test

Compacting factor test

Vebe test

Flow table test

Properties

               
 A basic desired property of concrete is good workability when the concrete is newly mixed. For example the concrete can be transport from the mixer, handled, placed in the moulds and compacted satisfactory. Concrete has high compressive strength and hardness, but lower tensile strength. This is because reinforced with materials that are strong in tension. This often refers to steel. Concrete also has adequate durability as a long term for all the building.

Use of concrete in infrastructure

Mass concrete structures

Large structures typically include gravity dams, such as the Hoover Dam, Itaipu Dam and the Three Gorges Dam: arch dams, navigation locks and large breakwaters.

Such large structures will generate excessive heat and associated expansion, even though it is individually placed in formed horizontal blocks. Post-cooling provided in the design is commonly used to mitigate these effects.

A network of pipes between vertical concrete placements is installed to circulate cooling water during the curing process and avoid damaging overheating.

 Mass concrete structure the Baths of Caracalla, in 2003

Pre-stressed concrete structures

Pre-stressed concrete is a form of reinforced concrete that builds in compressive stresses during construction to oppose those found when in use.

Weight of beams or slabs can be reducing by better distributing the stresses in the structure to make optimal use of the reinforcement.

Pre-stressed concrete structures

Bridge over the Sungai Selangor, Kuala Selangor, Malaysia