Lightweight Concrete Production

1. Introduction to light weight concrete

Lightweight concrete is mainly used as back-filling material. When talking about lightweight concrete, we refer to a concrete of which its specific gravity (density) is much more lower than normal concrete.

Basically normal concrete: 2.35 – 2.42 ton/m3 while lightweight concrete 0.80-1.40 t/m3.

Therefore final strength is not issue. Expected final strength would be usually lower 5 MPa at 28 dasy as such concrete contained of lot of air entrained.

The strength would be affected by type of lightweight aggregate to used.

2. Production Principle

Basically there are 2 ways to produce light weight concrete.

a. Cement/ Water/Sand/lightweight aggregate/ chemical additives (admixtures)

b. Cement/ Water/ Sand/ Chemical additives

By lightweight aggregate we can consider polystyrene balls, expanded clay for instance.  Chemical additives, we mainly means special air entrained agent such as Sika Lightcrete 1-500VP. This admixture ca entrained safely up to 30% of air entrained into the mix.

As per the use of the special air entrained, usually, the mix is batched for a designed volume the air entrained is measured in order to determine final volume of the concrete batched. Indeed in term of concrete production it is important to know about about which volume we are talking, we are referring to:

For instance: Expected air entrained 30%

Volume of fresh batch 1000 liters -> initial ar development 30% –> final hard volume ~1.3 m3

The History of Windmills

Down through the ages, mandkind has used the natural and renewable power of wind for windmills. A windmill is a machine that use sails or blades to harness the kinetic energy of wind and convert it to mechanical energy to grind grain and coin, saw timber, and draw up water for irrigation and water supply.

The first practical windmill dates from 9th-century found in Persia and was likely a vertical shaft with six to twelves sails. Windmills of this type were used throughout much of Islamic world, and introduced to Europe through Islamic Spain. In China, a similar of vertical shaft windmill with rectangular blades was used in the 13th century.

A difference design was introduced in northern France in the 12th century that became the standard for Europe. A horizontal shaft was mounted to an upright body and buck that could be rotated to face the direction of the wind.

By the end  of 13th century, windmills mostly were made of brick with a timber cap that rotated rather than the body of the mill. This made it possible to build windmills that were much taller, allowing sails to be larger, making it possible to work even in low winds.

A small auxiliary set of sails, called a fantail, at the rear of the cap helped keep the sails facing the direction of the wind. With the industrial revolution, windmills became less important sd  primary industrial energy force and were largely replaced by steam and the internal combustion engines.  They did experience a brief heyday during and after World War II due to the lack of fuel, electricity and other means to run machines. In Holland, about 100,000 were in operation by end of the 19th century. Today, there are bout 1000. In the US, where windmills were used on farms in the Midwest to pump water, there were about six million windmills by the end of the 19th century of which only 15,000 remain.

The modern generation of windmills, more properly called Wind Turbine, are used to generate electricity from wind power. The largest turbine can generate uo to 6MW of power

The Growing Field of Construction Management

Earning a Construction management degree online has quickly become a popular way to jump start a career in construction project management. The field of construction management has been growing over the last ten years. This can be attributed to many different factors; the first of which being that development companies in the construction industry have started placing very high value on employees who can successfully perform construction project management. This is really no surprise considering that good construction management can make or break a complicated project. It requires an extremely strong level of detail-oriented work, communication and management skills, as well as a solid understanding of all industry-standard technologies and software.
If you are interested in construction management for your career, there are several steps you can take to qualify for the type of construction management jobs available today. The first step is to look for higher education institutions that offer a construction management certification or degree. Many traditional universities now offer variations of these degrees and you can also seek out schools that offer a construction management degree online.
If you have a fulltime job now and are hoping to increase your earnings potential without decreasing your current income, the best option may be for you to apply to a school that offers a construction management program and degree online. This will allow you to keep your job and finances in check while you work toward your construction management degree. In doing so, you can avoid costly out-of-state tuition fees, any relocation costs or additional costs of living that you may incur as a campus or university-based housing resident. The one important thing to remember is that the online school you apply to must be accredited. This not only ensures that any future employers will honor your degree, it will also ensure that you can easily transfer your credits to another school that offers a construction management program and degree if necessary.
Another great way to learn more about construction management and gain the hands-on experience you will need is to apply for an apprenticeship or internship with a company that has one or more fulltime construction management positions. If you already have a fulltime job and do not have enough time for an internship, you could find a mentor who can teach you about the job after hours, or you could even ask to shadow a construction management supervisor for a day to get a better understanding of what the job is like.
These tactics may be time consuming, but you can keep reminding yourself that it will be worth the time and energy spent: the average salary for construction management positions was approximately $120,000 in 2011.
However you go about gaining your degree and work experience in the field of construction management, it will be a step in the right direction for your career and your life.

Relieve Your Stress By Doing A Garden

There are numerous reasons for working with a garden, from wanting to grow fruits and vegetables or flowers, to having an attractive and appealing landscape. Nevertheless, for a lot of of us, working with a garden can be therapeutic. So long as you approach gardening as tranquil and enjoyable it will relieve stress. It won’t be a stress relief if you consider it as a chore that you want to get done quickly.

Once you concentrate on your gardening goals, you will be able to relieve your stress. You might easily get rid of the tension and stress by doing things like digging, chopping and hitting when you are gardening. Many people alleviate their stress by striking dummies, slamming pillows, or hitting into thin air, and that is why the motions of gardening are good for people. An outlet for aggressions which are pent-up can be supplied by intense activities, but that certainly isn’t the only way. Your body’s stress could be just as easily relieved by walking around your garden, enjoying everything you have created. Your state of being can be improved by taking in the fragrances, the colors and the designs of your garden. You’ll find that your stress has become reversed as a result of all the hard work you did in your garden.

What is important is that you help to make horticulture a fun hobby for you. It’s best to make a list of things you need to do and follow the list. It does not have to be done at one time, or in a day, otherwise you will just produce stress. You should do gardening like how you do your workouts. Essentially you want to work hard, take required breaks and drink a lot of water. Teach your young ones ways to garden, and you can use the experience as a way to bond with them. Your children will remember the experience for the rest of their lives while learning excellent life skills.

Stress and anxiety has led to a lot of persistent illnesses for many people so it is important that you learn how to relieve stress. If you’re able to achieve that as a result of gardening, you should do it now. If you don’t have any space, there are plenty of programs that can help you grow and garden. Gardening might be good for relieving your stress, but it can benefit you in various ways, as well. You’ll be able to grow fruits and veggies that you can share with everyone to enjoy. Working in sunshine while gardening can help you with vitamin D intake for your body. You can expect to feel happy and even refreshed.

Gardening can be a fun activity that will relieve your stress. It’s also a great way to get your children and yourself nearer together. It may be a beneficial hobby you do the rest of your life. You will also have the advantage of saving money by growing your own fruits and vegetables.

Fibre Reinforced Concrete

Conventional concrete containing discontinuous discrete fibres is called fibre-reinforced concrete. Fibers of various shape and size produced from steel, plastic,  glass, carbon and natural materials have been used.

However for any reinforcement to be effective, it must be stiffer than the concrete matrix that is reinforcing. Generally the less stiff fibres (made from plastic and natural materials) only offer benefits in improving the tensile strength of plastic and semi-hardened concrete and are therefore mainly used to reduce plastic shrinkage and plastic settlement cracking. The stiffer fibres improve both the tensile strength and the toughness of harden concrete.

The most widely used stiff fibre is steel. Low volume fractions of fibres (less than 1%) are used to reduce shrinkage cracking. Moderate volume fractions (between 1% to 2%) increase flexural strength, fracture toughness and impact resistance. High volume fractions (greater than 2%) lead to strain hardening of the composites. The shape and length of the fibres also play a role in the fibres’ effectiveness in improving the properties of the concrete. The use of fibres in concrete can have a marked effect on the workability of the concrete and this need to be taken into account  in the mix proportion of fibre-reinforced concrete.

Currently a great deal of research is being undertaken into the use of ultra-high-performance fibre-reinforced composites. One of the benefits of these materials is extremely high ductility. Fibre-reinforced concrete has been used for precast panels, airfield and highway pavements, industrial floors and in spraying concrete for slope stability and underground mining applications.