Power Trowelling

One of the major problems when it comes to concrete flooring is that you can be left with a bumpy dusty floor that is effectively unfinished. Machine aided manufacture helps to correct the natural mistake that concrete creates when drying.

Finishing a concrete floor is all about timing, get it wrong and you could be left with an uneven floor or a large amount of mess to clear up. A power trowel is used to create a flat and robust finish on a concrete floor, such as a patio floor or an interior kitchen floor. Power trowelling can be achieved on any size of surface by either a manual walk-behind trowel or a ride on trowel.

How do they work?

Power Trowels come with either one blade or multiple blades that spin continuously from within a safety cage which rotates on the surface of the concrete to provide a smooth result. They are used to smooth out any imperfections on the surface of the concrete that may cause bumps or ridges when hardened. The rule of thumb when using a power trowel is to place a foot into the concrete and make sure that the mark does not make more than a 3mm imprint, with as little water residue as possible (which means, avoid cold damp days). If you leave the concrete to thicken too much then the blades will not be able to cut into the floor and will damage the equipment which is obviously not what you want. If the surface is too soft then the machine will tear up the surface and leave massive imprints on the floor. The flooring must be able to take the weight of the trowel and in most cases the operator as well.

Benefits of Power Trowelling

* Provides a strong durable result

* Manual use allows for small areas to be quickly and efficiently smoothed

* Sit on machine or a manual push machine for a variety of different surfaces areas

* Gets rid of any visible imperfections on the surface

* Petrol or electrically driven

* Blade option variability

There are a variety of different blades that can be chosen that will all deliver a different finish. Whether you are looking for a certain type of finish or have a surface with an abnormal quantity of imperfections you can choose which blade will best suit your situation. Obviously the most important feature for a power trowel is the ability to be balanced and provide a level floor. For those areas where there are excessive dents and ridges the blades can be adjusted accordingly. Care must be taken at all stages so that the result is the best that can be achieved.

Geotechnical Core Logging

Geotechnial Core Logging is the process of recording rock descriptions on boring logs, where primary means of communicating rock properties are used in the design and construction of underground works including foundations in and on rock, rock slope and tunnel support, and excavations in rock. The quality of rock descriptions can have far-reaching implications for the success of a project. An appropriate level of detail (as determined by the project-specific end use objective) must be collected and conveyed.

Important considerations for geotechnical core logging include: 
1. Rock descriptions developed for each rock material unit, defined as discrete mass exhibiting a different set of geologic and engineering properties than adjacent materials. Material unit-based rock core logging minimizes the risk of overlooking design-critical rock mass conditions. 
2. Material unit descriptions should be constructed using a standard descriptive code consisting of well-defined terminology arranged in a consistent format. 
3. Standardization of the rock core logging descriptive code (at least for individual projects) will result in more useful rock descriptions to facilitate geo-engineering interpretation, spatial correlation of material units, and engineering analysis for developing design recommendations and construction considerations.

The following steps are suggested during the geotechnical core logging process:

1. Clean the core of drilling fluids or mud. 
2. Mark major structures, proposed point load testing locations, and depths (every 1-2 metres) on undisturbed core in splits. 
3. Photograph the core in the splits (if using triple tube method) with a scale placed in the picture and a whiteboard indicating what depth the core has been obtained from. 
4. Complete the Discontinuity and core description logs. 
5. Transfer the core from the splits to a labelled core box. 
6. Once a core box is full, take a single photograph of the core box with a scale. 
7. The steps are detailed in the following sections.

One of the most important things to do at the drill rig is photograph the undisturbed core in the splits. These photos may be used later to confirm televiewer images and will be an invaluable resource on the rock mass and for review of the design work.

Proper core photos require that the core be cleaned prior to photographing. When core is covered in drilling mud, structural information can be obscured making it difficult to determine lithologies. Take the time to properly clean the core. The core should be wet if possible as some structural features do not show up on dry core so make sure to wet it down with a spray bottle or paint brush.

Asphalt Pavement Maintenance Planning

Do you have an asphalt maintenance plan in place for your facility? As asphalt surfaces age, erode and become brittle, proper periodic assessment and treatments are essential in maintaining a quality surface and infrastructure. The appropriate course of action can save time and money by making sure the maintenance applications are matched to the severity of the pavement problems.

Understanding Defects

There are typically three types of asphalt failures: Surface, Bond, and Structural Failures. For surface failures there can be raveling, and transverse or longitudinal cracking problems. Raveling is the loss of aggregate from the surface as a result of abrading action from wheels. Longitudinal cracks run in the direction of traffic and transverse cracks are 90 degrees to longitudinal cracks. Longitudinal cracks are typically caused from shrinkage.

Bonding failures are usually in the form of slippage between two layers of surfacing causing cracks in the upper layer. In some cases the combination of bonding and crack failures causes the top layer to flake off in chunks.

The most severe defects are structural cracking which can include fatigue cracking and rutting. Fatigue cracking results from the surface being flexed up and down from heavy loads going by. The cracks are very close together and look like an alligator's skin. This defect occurs when the underlying road section can no longer support the loads being applied to the pavement. One heavy truck can flex and damage a road more than thousands of cars passing over the same spot. Rutting is a depression of the pavement in the wheel path and is usually continuous throughout a pavement. It can occur in just the asphalt layer or throughout the entire infrastructure of asphalt, base, and soil.

Types of Treatments

The difference types of actions one can choose will vary with the defects and extent of damage found on the pavement surface. The potential solutions can include surface seal coats, crack filling, slurry seals, selective dig-outs and patching, or full overlays.

Within the use of surface seal coats, there are several to choose from. They include slurry, cape, micro-surfacing, fog, and rubberized chip seals to name a few. A fog seal contains no aggregate or sand and is spray applied to keep the surface aggregate in place. A surface seal coat is a mixture of sand and asphalt emulsion with other fillers. It provides a uniform black surface and protects from UV damage and reduces water intrusion. A slurry seal consists of emulsified asphalt binder, a graded fine aggregate additive and water and is applied by machines with pressure.

An overlay is used over the top of an existing pavement surface to strengthen and protect the original structure. It can be applied at various thicknesses and also can be rubberized. Sometimes milling is required before the overlay when excessive heights are an issue to prevent any potential trip hazards. Also the use of paving grids and fabrics over the top of an existing cracked pavement can provide additional strength and water intrusion protection.

Asphalt crack filler machine is a kind of asphalt crack repair machine which is suitable for filling the cracks of road, expressway, asphalt and concrete pavement of municipal, airports, squares, industrial parks,as well as filling cracks of complicated and irregular pavement. As an indispensable road maintenance machine, it is mainly used for preventive maintenance of road surface diseases and in conjunction with road grooving machine and air blower. We use the most advanced irrigation sewing technology and produce and produced a variety of models of asphalt crack filler machine for sale, which will be the good choice for customers. Feel free to send us email to contact us more about your requirements, we will reply you in 24 hours. 

How To Control Dust When Concrete Cutting

Construction workers and anyone who ever performed concrete cutting knows about their exposure to concrete dust and how harmful may it be to their health. It can lead to serious health consequences depending on the length of exposure.

If you are not properly protected while cutting concrete, dust can negatively affect your health system and lead to chronic breathing problems or any other respiratory illness. There are many construction workers who have fallen ill due to asthma, silicosis and even lung cancer.

Everyone involved in the construction industry knows that dry cutting with gas-powered concrete saws should not be used anymore because the exposure level to dust is enormous. Even if you are using an appropriate mask to reduce personal exposures, dust is still filling the work area and risks other workers' health and the entire neighbourhood beyond. Also, if you're working in an enclosed construction space rather than an open air, the concrete dust trapped in the space is forcing you to inhale it.

There are two methods that appeared to be successful for controlling dust when cutting concrete and to minimize its exposure to the environment.

1. Wet Concrete Cutting

The regular use of water controls of gas-powered concrete saws is a clear and effective way to reduce the level of respirable dust. A small amount of water can go a long way toward reducing dust if you have to cut concrete with a circular saw or a diamond blade.

There are many wet cutting techniques you can try. For example, pour water onto the rotating cutting blade while in use; or pump water directly onto the cutting area while the saw still operates. Water can be supplied using a portable pressured tank created by many manufacturers of concrete cutting saws. These tanks contain at least eight litres of water and they are effective for a period of 15 minutes of cutting. A ratio of ½ a litre of water per minute is considered as a standard rate to reduce dust emissions. After that, the tanks have to be refiled. This is the preferable method since it's flexible to carry around the site as long as there is a water source for any further refiles required.

2. Protective Measures

It is important to take some protective measures in order to reduce the risks associated with dust from cutting concrete. This includes wearing masks and using safety glasses. You should know to select a proper mask that is specifically designed to provide protection against concrete dust. Mask filters will become blocked after a period of time and they will need to be replaced regularly. Any other workers on the construction site should be wearing masks too.

Using proper safety glasses is extremely necessary to keep your eyes protected during the cutting process. Not wearing this type of glasses can result in small irritation or permanent damaging of the eyes.

Other safety measures for workers are wearing good quality headgear, proper hearing protection and foot protection.

Employing both wet concrete cutting techniques as well as taking proper protective measures will provide the greatest level of dust control.

The Features of Hydraulic Concrete Wall Saw

1.High work efficiency. The machine can increase the working speed and shorten the construction time.
2.Low labor cost, large competitive advantage and suitable for large-scale cutting engineering.
3.Low loss cost. The safety, reliability and stability of hydraulic system itself greatly reduce the loss cost of construction equipment.
4.The static cutting technology used in hydraulic wall saw machine has become a construction and design concept.
5.With overload protection which can ensure the safety.
6.More powerful that can improve the cutting period and labor productivity.