- How to Fill Bubble Holes in Cement
- What Is High Alumina Cement?
- How to Clean a Cement Mixer
- How to Dissolve RTV Cement
- How to Match Concrete
- How to Fix Holes in a Concrete Driveway
- How to Make a Carport Cement Slab
- DIY Pour Fiber Cement
- How to Mix Soil and Cement
- How to Grow Tomatoes in Cement Blocks
- How to Use Cement Flower Pot Molds
- How to Render a Mix Ratio
- How to Mount Outside Lighting With Cement Siding
- How to Lay Stone Over a Concrete Patio
- How to Caulk Cement
A certain amount of air in cement mix is desirable. Air lets moisture expand and contract in a freezing environment without damaging the concrete. When you have bubble holes, also known as bug holes and honeycombs, on the surface of your casting, something has gone wrong. Your cement mix was too thick, the temperature too low, your mold release applied too soon, or you have poured the cement too quickly or vibrated the mold incorrectly. You can repair the surface cheaply and easily without recasting the surface or marring the finish.
Mix a new batch of cement or small amount of premix if the repair is small.
Clean debris from the surface and wet the repair area. Wetting the surface allows the repair batch to fill holes better and blend into the surrounding surface. Use an atomizer if it is a small or inside job.
Trowel and compact the cement into the bubble holes. If the hole is deep, wait 15 minutes or until the repair has begun to shrink, then resurface. Leave to dry overnight.
Water the repaired area lightly with a misting hose or atomizer.
When dry for the second time, buff lightly with fine sandpaper to minimize transitions.
Apply colored epoxy with a putty knife for small holes and cement paste with matching pigment for larger areas when repairing an indoor concrete countertop.
Wet sand the epoxy/cement paste when dry.
HAC is a carefully measured mixture of alumina and calcareous materials. These two materials are grounded together until a fine dust is produced (pulverizing materials is a standard process in all cement production). Limestone and bauxite are used in the production of the mixture.
HAC is created through chemical reactions through heat. The pulverized mixture of alumina and calcareous materials is placed in a furnace. This furnace contains pulverized coal, oil and has hot air blasts. The combination of these elements produces heat upwards of 1,600 degrees Celsius. This extreme temperature is necessary to the formation of HAC.
Standard cement sets through "hydraulic" chemical reaction (an interaction with water). HAC, on the other hand, sets with high temperatures. When the cement mixture is removed from the furnace it is in molten form. The molten HAC is removed from the furnace and placed into molds. Here, the HAC will cool off. Once completely cooled the molds are ready for use.
HAC has two main benefits. The first is its resistance to chemical interactions. This means HAC is able to withstand water damage and any other element it may encounter. HAC is also able to withstand frigid temperatures, making it a suitable building material in cold regions.
The major negative to HAC is "inversion." Inversion is the unique process in which disintegration occurs due to exposure to heat and water at the same time. The cement won't disintegrate immediately, but over time the cement will become weak and its structure becomes compromised. This makes HAC most suitable for cold regions.
Cleaning the Mixer
Shovel two scoops of gravel into the cement mixer. Fill the drum with approximately 3 gallons of water using a garden hose.
Turn on the cement mixer and rotate the gravel and water mixture for roughly 10 to 12 minutes. Adjust the angle of the drum so that the rock and water tumble up to the edge, ensuring a completely clean drum.
Empty the mixture into a wheelbarrow and dispose of in an out-of-the-way spot. Use clean gravel any time this method is used. Spray the empty mixer with water from the hose and allow it to air dry before transporting or storing it.
Use a grease product such as Crete-lease on the outside of the mixer to prevent cement buildup on the surface. Check with the owner of the cement mixer before applying this product if it is rented or borrowed. Some owners use their own products.
Coat the inside of the drum lightly with diesel fuel before mixing cement. Although, it is true that the cement will not stick to the drum, diesel fuel breaks down the composition of cement and ruins it. Use diesel fuel sparingly.
Put on gloves and then pour a small amount of solvent over the RTV cement, just enough to saturate the area covered by the cement.
Allow the solvent to dissolve the cement, reapplying solvent as it runs off or as the dissolving process slows.
Scrape the remaining cement away using a stiff scraper or straight razor.
Wipe away any cement residue using a lint-free cloth soaked in solvent.
If you're trying to match concrete, the first step you need to take is to search for the different color ranges of concrete in your area. It is nearly impossible to perfectly match concrete, but you can find the best color to match the existing concrete using this method.
After the new cement sets, try rubbing dirt into the area and then rinsing it off to see if you can get the colors to match a little better. (It is possible that over time the new concrete will be a closer match to the old concrete, but it's definitely not a guarantee.)
If the colors of cement are still very different from each other you can try an epoxy overlay. With an epoxy overlay you can cover both the old cement and the new cement for a better color match. There are many different types of epoxy overlays available.
Chip away loose concrete from the damaged area with a small chisel and hammer. The hydraulic cement will bond better to concrete that is not loose.
Brush away dirt and pieces of concrete from the area with a broom. The cleaner the area is, the better chance the repair will be successful.
Mix the hydraulic cement in a bucket with water according to the directions on the package.
Spread the cement into the hole using a cement trowel. Ensure the cement is level with the rest of the surface of the driveway. Fill in the entire area and smooth the cement around the affected area onto the good part of the drive. The cement will dry quickly and can be walked or driven on within an hour.
Excavate the dirt 6-inches from the top of the slab. Use a shovel. Dampen the earth and then tamp it with a hand held tamper to flatten the earth.
Place a 2-inch layer of wash stone in the hole. Level the stone and tamp it down.
Build a form around the hole using 2-by-6 boards. Connect the boards at the ends with 8-penny nails. If the boards run long, cut them using a circular saw.
Hammer 12-inch wooden stakes behind the form boards to hold the boards in place. Nail the stakes to the form boards using double headed nails. (Double headed nails are easier to remove when it's time to take the boards down.)
Put two runs of #4 rebar along the length of the carport. Suspend the rebar up from the dirt using rebar chairs that you can purchase at any home store. (If the rebar touches the dirt, or is exposed to air, it can corrode.)
Mix up a batch of cement in a rented cement mixer. Follow the manufacturer's recommended mixing procedure. Pour the cement into the hole, over the stone and rebar, 2-inches thick.
Use a trowel to smooth out the cement before it dries. Trowels come with long handles for reaching across cement slabs. Once the cement is smooth, let it cure for at least 48 hours.
Read the instructions on the cement mix bag before mixing the cement or adding a fiber additive. Mix the cement mix in the wheelbarrow according to the mixing instructions on the bag.
Add the fiber additive according to the directions on the fiber additive bag if your cement mix does not already contain a fiber additive. Add only as much additive as the directions indicate. You may have additive left over; it is better to have leftover additive than to go against the directions. Adding too much additive may cause negative stresses on the cement and may weaken the finished product.
Pour the concrete into the form for your project by tilting the wheelbarrow so the lip over the wheel faces down into the project area.
Even out the surface using a hand trowel. It is best to work your way from one corner across the project to the other to avoid having to repeat sections.
Allow the concrete to cure gradually. Concrete solidifies relatively quickly, but follow the instructions on the concrete mix to determine how long the concrete must cure to reach maximum hardness. Check the bag of additive to see if there are supplementary instructions which may change the drying time as indicated on the back of the bag of concrete mix.
Add the soil to the cement mixer first. This is especially important if the soil has clumps in it. Mix the soil until it’s smooth.
Put some water in with the soil if the clumps are stubborn. The water can help break them up and smooth out the soil faster.
Pour in your Portland cement and water to mix it smoothly, as well. The cement to water ratio can be about two to one but the consistency that you desire might require slightly more or less water.
Continue the mixing process until the soil, cement and water together have the consistency you desire for your project. If you’re not sure, consult with the label instructions on the cement.
Place your cement block in a sunny location, and tip it so that the holes that run through it are facing up.
Fill the holes in your cement block with finished compost.
Remove your tomato plants from their containers by tipping the containers on their side and gently tapping to release the plant.
Move the soil in the center of each cement block hole to create a pocket in the compost for the plant.
Place one tomato seedling in the compost in each hole, and move the compost until it is level with the first two leaves of your tomato plants.
Check the compost daily, and water whenever it becomes dry. The compost should feel damp to the touch.
Coat the inside of the cement flower pot mold with a release agent. Commercial products work, but you can also use vegetable oil, petroleum jelly or a blend of castor oil and denatured alcohol. To make the castor oil/alcohol mix, combine 2 oz. of castor oil with 16 oz. of alcohol. Apply the mixture with a spray bottle.
Mix concrete topping mix in a bucket with water following the ratios indicated on the concrete package. Topping mix is a good choice for cement flower pots as it does not contain stones and gives your flower pots a smooth finish. An electric drill with a paddle drill bit works well to mix the cement, but you can also use a small shovel or wooden spoon.
Pour the mixture into the cement flower pot mold. Tap the sides of the mold to release any air bubbles that may be trapped. Let the cement dry in the mold for 48 hours.
Flip the mold upside down on a sheet of plywood to remove the flower pot. Some aluminum molds require disassembling to remove them from the dried cement form. Allow the cement flower pot to sit for seven days before planting anything in it. This gives the concrete time to cure completely.
Determine the type of render finish desired. There are internal renders such as floating, glass-faced and floor screeding. There are external renders such as sand-finished base coat, sand-finished top coat and bag wash.
Refer to a chart, such as the one from Cockburn Cement, to find the appropriate mix ratio.
Use a measuring bucket to add the appropriate ratios to the wheelbarrow. For example, a bag wash exterior render requires one part cement, one part lime and five parts sand. So, add one bucket of cement and one bucked of lime for every five buckets of sand.
Add water to the mixture very slowly. Use a shovel to mix the materials. Keep adding water until the mixture feels like a soft putty. The mixture should stick to the trowel when it is flipped upside down. Do not make the mixture too watery.
Apply the render to the surface using the trowel until it is of the desired thickness. If multiple coats are required, allow each preceding coat to dry for three to seven days.
Choose a concrete anchor that is a size smaller than the holes in the mounting plate. For a 1/2-inch mounting plate hole, use a 3/8-inch concrete anchor.
Place the mounting plate against the piece of siding where you want to install the fixture. Mark the placement of all mounting holes with a marker or pencil.
Put on safety goggles. Drill through the marked areas on the cement siding equaling the same depth as the concrete anchors. Screw the concrete anchors into the drilled holes in the cement siding.
Place the mounting plate back over the cement siding. Pull any necessary wires through the hole in the plate so that you can attach the fixture and operate it properly. Screw the plate into place with concrete screws and a power screwdriver. Screw all screws in lightly, then tighten them fully after all screws are in place. This will help align the mounting plate correctly.
Connect the fixture to the wires, then attach it to the mounting plate.
Sweep off the patio. Hose down the surface very well. Scrub it down with additional water and dish soap, getting a good lather. Scrub it free of all dirt, grime, moss and anything else that might interfere with the performance of the cement. Rinse it thoroughly. Let it dry completely.
Lay out your stones, placing all of them exactly where you want them to be on the patio. Put between 1/2 inch and 3/4 inches of space between them. If cuts are necessary at the edges, make them with your masonry saw.
Mix your cement in the wheelbarrow with your shovel. Starting at one corner, lift up one of the stones and, with your cement trowel, cake the back of it with about half an inch of cement. Spread another half an inch of cement on the concrete patio, in the spot where you lifted the stone. Press the stone back into place. Press just firmly enough that cement starts to come up the sides.
Repeat the process for each stone on the patio. For each group of four or five stones that you lay, trowel additional cement into the spaces between them, smoothing it out at the top and scooping any stray cement off the surface of the stone. Continue until all the stones have been cemented down and all the spaces between them are filled with cement.
Mist the entire patio with your garden hose. Let it dry overnight. Mist it again in the morning and at night, for the next two days. When it dries on the third day, it's ready for use.
Clean and wash the area of all debris, and then allow it to dry fully.
Insert the mortar and concrete caulk tube into the caulking gun.
Make a 1/8- to 1/4-inch “bead” of caulk by cutting the tip off the end of the tube with a utility knife.
Touch the tip of the caulk tube to the area that needs caulking. Start caulking by pulling the caulk gun down the length of the joint. Stop the stream of caulk, and wipe the tip with a wet towel.
Push the caulk into the joint using a soapy finger or putty knife. This makes a uniform surface and weatherproof seal.
Use a damp rag and your putty knife to clean off any remanding caulk.