Concrete mix design

In order to calculate amount of cement, sand and aggregate required in 1m3 of concrete , you have to know about different grades of concrete. Based on strength Different grades of concrete is classified into  M5, M7.5, M10, M15 etc., wheras M stands for Mix and the number behind M stands for characteristic Compressive strength(fck) of the concrete in 28 days when checked in direct compression test. Tthe ratio for M20 grade of concrete is 1:1.5:3 that mean 1 part of cement, 1.5 part of sand (fine aggregate) and 3 parts of aggregate (crushed stone) in volume and then batched for mixing. To know the Concrete Mix Design follow below:-

Mix Design (M) = Cement: Sand :Aggregate

10 construction technologies

video click it

5 New Trends in Construction and Building

As the economy improves, often the construction business does as well—but that industry is still looking for sound strategies, not just structures. After the housing dip of a few years ago, value is still on people’s minds as there isn’t a guarantee that another downturn couldn’t be around the corner.

Mike Miller, the Mid-Atlantic Division leader for Southland Industries, Dulles, VA, a mechanical engineering building firm, and Jim Snyder, director of operations for construction company Warrior Group, Columbus, OH, give us insights into the trends to look for this year.

1) Single-Design Model

Miller points out that traditionally, engineering documents were created then given to the contractor to re-draw with different information. Now, to save time and money, there’s a shift to have it all in-house from engineering to coordination, creating a one-stop shop. Through the proper coordination, models can and should, says Miller, go through engineering right into construction. “Thirty month projects can get turned into 24-month projects,” he adds.

 Top trends in construction and building, from single-design models to permanent modular construction, have an impact on the future.

2) Materials

Miller, who has a degree in architectural engineering, says materials such as adapted sheet metal are popular as a guaranteed pressure class for high quality, but it’s how materials are being used that makes the difference. Going to prefabrication off-site for construction fits right into the ongoing theme of improving schedules. “Instead of joining one piece of duct work you can join 20 feet of duct together,” Miller says. “It’s about moving more work from the field into the shop.”

3) Energy Efficiency

Energy consumption is always on the mind in construction, says Miller. He notes systems that recover energy through heat wheels and occupancy sensors are becoming vital. An example of the latter are the countless interior conference rooms that can be left empty for weeks. By recognizing carbon dioxide in the room, a sensor changes the ventilation and, therefore, the energy needed.

4) Permanent Modular Construction

Snyder offers that permanent modular construction will be a huge trend in the coming years, saying the construction can easily last more than 50 years. “It looks exactly like commercial construction and can be done using many of the same things: metal studs, concrete, or even wood.” Snyder says modular construction fits particularly well when you’re in a time crunch, from fast food restaurants that need to go up quickly to army barracks for military deployment. “It also allows you to have an easier time doing the building as you go,” he says. “Instead of building 100,000 square feet, you can do 25,000 and then later, add on.” Snyder, who has a degree in construction science, sees it also becoming a part of high-rise construction and being particularly popular for how it fits in with LEED requirements. The key, he says, is changing people’s minds about what they envision. “They see it as boxes,” he says, “but it can be so many things that you want it to be.”

5) Possibly…You

According to Miller, well-rounded civil engineers who can go beyond calculations to fitting into these coordinated engineering design models will render themselves invaluable. The only question is: Are you flexible enough for the challenge?

FLOOR FINISHES AND HOW TO CHOOSE THEM

When choosing a floor finish, keep in mind the following:
How slippery or smooth it is; do not use very smooth finishes in bathrooms and balconies
How abrasion resistant it is - do not use soft, quick wearing finishes in areas with heavy foot traffic. Marble and wood have low abrasion resistance, for example, and granite and cement tiles have high abrasion resistance.
Whether it is chemically neutral - some finishes react with acids, and should not be used in kitchens
The climate: wood and carpets are perceived to be warm, so use them in cold climates, and stone and tile are perceived to be cool, so use them in warm climates - unless you have underfloor heating or cooling, which changes things.


A detailed description of each of the most important floor finishes follows.
STONE


Stone is a great floor finish and is affordable in many countries; Italy and India are both known for the variety and quality of stone they produce. There is a great advantage to stone that is almost unique to floor finishes: you can polish it, and thus make it look and feel like new, at any time in its life.

Granite is a volcanic rock (it was originally lava, that cooled to form solid rock) that has the following properties:
It is very hard, strong, and abrasion resistant
It is resistant to acids
It can be polished to a mirror-like smoothness

These properties make it a great choice as a floor or countertop finish. It can also be used to clad walls. However it is available mainly in dark colours - black, red, grey - with the possible exception of Kashmir White Granite. This darkness in colour does tend to limit its use in certain areas.

Its surface can also be worked to produce a variety of textures other than smooth: granite can be flamed, water blasted, sand blasted, bush hammered, or tumbled. These rough finishes are mostly used outdoors, on pathways. The famous cobblestones of Europe are granite, for instance.

Marble is a metamorphic rock (meaning that it was made by the intense pressures and heat deep within the earth), and has the following properties:
Most marbles are soft, and not very abrasion resistant
They are not resistant to acids
They can be polished to a mirror finish
It is translucent - light can pass through it to the extent of a few millimeters

Thus, marbles should not be used in high-traffic areas such as the entryways or staircases of public buildings - granite would be much better in those cases. Since it is not acid resistant, you should not use Marble under urinals (urine is acidic), and in kitchens, where lemon juice and other acids are present. But marble is prized for the beauty and richness of its finish; it also feelsvery special underfoot. It is available in a wide variety of colours, mainly light colours.

Sandstone is a sedimentary rock (rock formed by ancient rivers that slowly deposited material on their beds, that built up layer by layer over millions of years). It has the following properties:
It is abrasion resistant, but not always strong, as it is formed in layers.
It is usually highly resistant to acids
It has a rough finish, and cannot be mirror-polished, as it consists of grains

These properties mean that it is good for decks and external areas because of its anti-slip properties. Since sandstone looks and feels very different from granite and marble, it has become fashionable to use these in boutique stores. Steve Jobs famously saw a bluish-grey sandstone on a trip to Florence, and many years later insisted that that very stone be used in all apple stores because of its 'integrity'. The stone is quarried from an area reserved for apple, cut into tiles, and every piece graded individually for colour tone by master craftsmen. The tiles are then arranged so that pieces with similar colour are placed together, which makes them seem more uniform to the eye. It is obtained from this quarry, if you're interested.