Handyman Guide > Building Materials: Mixing Concrete

Mixing Concrete. The proportion of cement, sand, gravel, and water used for mixing concrete depends on the class of work to be done and on the condition of the sand and gravel. These two materials are seldom completely free of moisture, and this must be taken into account when adding water. The amount of moisture in the aggregates will vary from, a damp condition to very wet. The water required for very wet aggregate is considerably less than that required for damp aggregate.

The strength of concrete depends upon the union of the water and cement to form a paste which, when hard, will bind the particles of sand and gravel together. Accordingly, it is very important that the proper portions of water and cement be, maintained. The table gives recommended quantities of water for various jobs. Make up a trial batch of concrete, using this table as a guide. If the mixture is too stiff to work, use less sand and gravel in the next batch. If the mixture is too wet, add more sand and gravel. Do not change the amount of water, as this will affect the bonding properties of the mixture. In other words, keep the ratio of cement to water as set down in the table. Control the workability of the mixture through the use of more or less aggregate. Always make up a trial mixture of concrete, and get it right, before mixing up a large batch for the job.

Concrete that has been properly mixed can be poured into a form with ease and packed down until it forms a dense mass. The concrete should be plastic enough so that the pebbles or gravel will not fall out when the mixture is handled. There should be no space between the elements of the coarse aggregate. The stiffness of the mixture varies with the job, so that the mixture used for a garage floor can be stiffer than that used for small forms.

Mixing the various ingredients together should be done with care. To make certain that the right amount of each material is used, have a pail marked in quarts and gallons for measuring the water and a bottomless box for the sand and coarse aggregate. The box should be built to hold exactly one cubic foot. A bag of cement contains one cubic foot. There is no measurement problem except when mixing up a small mass of concrete. All ingredients must be measured out carefully. Do not try; to judge the quantity by eye.

Almost any flat, clean, waterproof surface can be used for mixing concrete. While machine mixing is always preferred, the home mechanic will seldom find this very practical unless he is doing a job big enough to warrant the renting of a mixer. Excellent concrete can be mixed by: hand, providing it is done thoroughly. Thorough mixing is essential to good concrete; it is the thoroughness of the machine mixer that makes it so efficient.

A garage floor, or a platform built of tongued and grooved lumber, is excellent for mixing concrete. Measure out the quantity of sand in accordance with the type of mixture and spread it on the surface of the mixing platform.

Measure out the cement and spread it over the sand. These two materials should be mixed together until they form a mass with a uniform color. There should be no streaks, an indication that the work has not been done thoroughly. After the sand and cement have been mixcd, measure out the coarse aggregate and spread it over the mixture. Continue mixing until the pebbles or gravcl are well distributed throughout the sand and cement. Measure out the correct amount of water and pour it into a depression formed in the middle of the pile of dry concrete. Start mixing again.and continue until there is no question that all the materials have been combined and the water distributed throughout the mixture.

The concrete should be placed in the forms, or wherever it is to be used, at least thirty minutes after mixing. This means thirty minutes after the sand and cement are mixed. Remember that sand contains some moisture, and this acts upon the cement when the two are combined.

Spade the concrete, when it is put in the forms, to make it dense.

Too many home concrete jobs have been ruined by not giving the concrete time to dry before stripping off the forms. Concrete does not dry by the evaporation of the water but by a chemical change. It takes approximately ten days for concrete to dry enough so that the forms can be removed. During this period of curing, the concrete should be kept moist and in shade. Cloth, paper, or straw should be placed over it and occasionally sprinkled with water. Concrete should not be mixed in freezing weather.

Coloring Concrete. Concrete may be colored by mixing coloring powders into it while still dry. Paint and hardware stores sell these powders.

Outside concrete jobs such as driveways and terraces can be colored best this way, better than by paint because they will not be damaged by moisture and the color will not fade as the surface is worn down. You can buy concrete stains which will give nearly the same result.

Dusty Concrete. It is very important, when making a concrete floor, that enough cement is used so that the concrete is not dusty. A floor in this condition can be remedied by using one of the prepared concrete hardeners.


Continue to Cement Mortar



Tools and Materials
Hammers - Handsaws - Screwdrivers - Chisels - Brace and Bit - Hand Drill - Brad Awl - Planes - Files - Measuring Tools - Rules - Squares - Marking Gauge - Levels - Pincers - Nail Set - Drawknife - Cabinet Scraper - Small Tool Kit - Putty Knife - Pliers - Wrenches - Paint Scraper - Sharpening Tools - Nails - Wood Screws - Corrugated Fasteners - Mending Plates - Bolts - Abrasives - Woodworking Glue - Splices and Joints.

The Workshop
Equipping the Workshop - Heating - Fire Precautions - The Workbench - Saw Bucks - Tool Rack.

Home Construction
Elements of the House - Building Materials - Lumber - Molding - Kinds of Wood and their Characteristics - Plywood Wallboard - Roofing Materials - Concrete - Mixing Concrete - Cement Mortar - Concrete Forms - Concrete Blocks - Cinder Blocks - Bricklaying - Fieldstone - Anchoring in Masonry - Soldering.

Furniture
Upholstered Furniture - Furniture Upkeep - Removing Stains - Removing Dents - Leather Upholstery - Cane Seats - Furniture Repairs - How to Repair Breaks - Levelling furniture - Remodeling Furniture - Polishes and Polishing - French Polishing - Painting Furniture - Sticking Drawers - Metal Furniture.

Painting
Paint Brushes - Storing Brushes - Varnish - Water Paint and Plastic Paint - Types of Paint - Paint Thinners - Mixing Paints - Preparing the Surface - Painting Flaws - Removing Paint - Exterior Painting - Painting New Wood - Repainting - Metal - Interior Painting - Calcimine - Painting Woodwork - Old Wood Trim - Staining - Fillers - Varnishing - Bleaching - Enameling - Painting Radiators - Painting Concrete - Shingles - Stoves and Stove Pipes - Whitewash.

Heating
Home Heating Systems - Chimneys - Coal Furnaces - Fuels - Burning Wood - Furnace Dampers - Starting a Coal Fire - Removal of Ashes - Coal Stokers - Oil Burners - Kerosene Heaters - Thermostats - Boiler Dampers - Fuel Economy - Warm Air System - Steam System - Vacuum System - Hot Water System - Radiators - Boilers - Maintaining the System - Insulating the System - Home Insulation - Storm Windows - Weather Stripping - Insulating Your Home - Blanket and Rigid Insulation - Unfinished Attic and Exterior Walls - Winterizing a Cabin - Preparing the foundation - Winterproofing a Cottage - Fireplaces - Reducing Condensation - Humidity.

Plumbing
The Plumbing System - Fresh water supply - Low Water Pressure - Hot Water System - Hot Water Heaters - Hot Water Tanks - Dirty Hot Water - The Sewage System - Sewage Disposal - Cesspools - Septic Tanks - Clearing Sewer Pipes - Clearing Drains - Plumbing Traps - Toilet Traps - Noisy Plumbing - Leaks in Water Tanks - Frozen Pipes - Clogged Water Pipes - Hard Water - Faucets - Shower Mixing Valves - Leaky Flush Tanks - Flush Valves - Removing Toilet Bowl - Leaky Pipes - Draining the Plumbing - Sealing Traps - Draining the Heating System - Types of Pipe - Insulating Pipes - Water Corrosion - Cleaning Fixtures.

Electricity
Definition of Terms - Ohm's Law - Alternating and Direct Current - Sources of Electrical Power - The Electrical System - Overloading the Circuit - Rewiring - Reading a Meter - Precautions - Fuses - Types of Cord - Splicing Wires - Replacing Plugs and Switches - Home Lighting - Electric Motors - Signaling System - Transformers - Burglar Alarms - Repairing the System - How to Install a Bell System.

Sign up for our weekly newsletter about how to start a handyman business. Get tips for finding clients, managing work and more.

More articles about starting a handyman business:

How to Start a Handyman Business

Handyman Business Cards

Handyman Clients: How to Find the Best Ones

Are You Cut Out to Be a Handyman?

Tools for a Handyman Business

Payment Options for Handymen

How To Advertise a Handyman Business

Customer Service Tips for Handymen

Choosing a Name for a Handyman Business

Record Keeping Basics for Handymen

Being a Handyman Versus Having a Handyman Business or a Franchise

Getting a Website for Your Handyman Business

Getting Paid Upfront: Deposit Policies for Handymen

How Much To Charge Per Hour

Should You Charge by the Hour, or by the Job?

Insurance for Handymen

Handyman Business Book Reviews

The Handyman Guide: How to Fix and Build 1000s of Things Around the House