Effect of Silica Fume to Water Permeability of Concrete

 

Water permeability of concrete can be reduced by up to 100 times through the use of Silica fume.

Test by some independence authorities indicates that so called waterproofing admixtures had no effect on water permeability of concrete. Rather that supervision and improved mix designs associated with such systems can lead to a more impermeable concrete. It should be noted that permeability of concrete is not a simple function of its porosity but depends also on size, distribution and continuity of the pores.

Pores in concrete are reduced significantly with the inclusion of silica fume and illaries reduced through reduced bleeding and production of denser paste. The permeability is lower the higher the cement content of the paste i.e. the lower the water/cement ratio. Values obtained for pastes in which 93% of cement has hydrated. It is the permeability of the paste that has the greatest effect on the permeability of the concrete. Water vapor transmission of concrete is reduced by a decrease in the water cement ratio. A decrease in water cement ratio from 0.8 to 0.4 decreases  the  vapour permeability by 50-65%.

Vapour permeability, however, decreases as the relative humidity decreases, an increase in relative humidity decreases the airfilled pore space available for diffusion. It follows the that if the moist side is for instance saturated an increase in the relative humidity of the  dry side reduces the vapor permeability.

The permeability of concrete is reduced by the use of silica fume in combination with superplasticizers which reduce the water cement ratio up to 30%.

Home Building Information – Learn from very basic things

 

Do you love to stay in your home? Many people do, because they think that their home is perfect. In order to have this feeling, they actually spent a lot of time and effort to create a quality house indeed. This article is just a brush up about home building, not really an advice, just some important notes for your consideration.

You would find that there are plenty of people who are experienced with home building nowadays. Since there are more and more people who have a house, they would spend the time to read books and study information about home building. Gradually, they would have the techniques for this and they would be experienced by working on their own house.

If you want to learn home building, you should first try to learn about how to match the color of the furniture and the wall. Usually, some people would not know this. If you want to have a simple style in your house, you can consider using white wall and purchasing wooden furniture. Black furniture can also work but black leather furniture would be preferred to the plastic ones.

During the work of home building, you should also remember that the best home would be the home which can be built within budget, instead of the home which is built with millions of dollars. As long as you find it comfortable to stay in the house, you would regard it as the best house and there is not a need for you to make everything grand in your house indeed.

You can try to check the license of the contractor and also the bond status. You would be able to ask the experience of some customers who have tried the service before. They would be able to give their personal experience as the objective review of the quality of services from those contractors. Therefore, you can consider trusting them.

In conclusion, home building can be something tiring if you do not have the experience before. You would find that it is not something easy at all for you to get the right direction of home building if you are new to this. Therefore, you should try to consult someone who is experienced or professional. If you do not want to hire someone because of the budget concerns, you can try to search online because there are people who are experienced with home building and they would possibly give you suitable pieces of information about home building which can give you insights.

What is Civil Engineering?

This definition of Civil Engineering is found at Answer.com. The tasks of civil engineering now come larger and larger.

Civil Engineering is a branch of engineering that encompasses the conception, design, construction, and management of residential and commercial buildings and structures, water supply facilities, and transportation systems for goods and people, as well as control of the environment for the maintenance and improvement of the quality of life. Civil engineering includes planning and design professionals in both the public and private sectors, contractors, builders, educators, and researchers.

The civil engineer holds the safety, health, and welfare of the public paramount. Civil engineering projects and systems should conform to governmental regulations and statutes; should be built economically to function properly with a minimum of maintenance and repair while withstanding anticipated usage and weather; and should conserve energy and allow hazard-free construction while providing healthful, safe, and environmentally sound utilization by society.

Civil engineers play a major role in developing workable solutions to construct, renovate, repair, maintain, and upgrade infrastructure. The infrastructure includes roads, mass transit, railroads, bridges, airports, storage buildings, terminals, communication and control towers, water supply and treatment systems, storm water control systems, wastewater collection, treatment and disposal systems, as well as living and working areas, recreational buildings, and ancillary structures for civil and civic needs. Without a well-maintained and functioning infrastructure, the urban area cannot stay healthy, grow, and prosper.

Because the desired objectives are so broad and encompass an orderly progression of interrelated components and information to arrive at the visually pleasing, environmentally satisfactory, and energy-frugal end point, civil engineering projects are actually systems requiring the skills and inputs of many diverse technical specialties, all of which are subsets of the overall civil engineering profession.

Some of the subsets that civil engineers can specialize in include photogrammetry, surveying, mapping, community and urban planning, and waste management and risk assessment. Various engineering areas that civil engineers can specialize in include geotechnical, construction, structural, environmental, water resources, and transportation engineering.