Corrosion of reinforcing steel and other embedded metals is the leading cause of deterioration in concrete. When steel corrodes, the resulting rust occupies a greater volume than the steel. This expan- sion creates tensile stresses in the concrete, which can eventually cause cracking, delamination, and spalling (Figs.
The organic chemicals which have been found to be effective as concrete dissolvers generally include organic acids such as oxalic, acetic, lactic, citric, tannic and humic acid as well as combinations of these acids and other organic compounds such as anhydrides or ethers of the above, the most widely used being ...
What are the most common causes of concrete deterioration? Chemical attack, overloading and impact, carbonation, dry and wet cycling, and fire are major causes of concrete damages.
There are a few factors which lead toward soft concrete. Excess water is the biggest culprit but we also have to consider the following; poor or insufficient curing, too little cement, carbonation, incorrect proportion of trace ingredients such as pozzolans or shrinkage additives.
The presence of air voids in concrete greatly reduces its strength . Approximately 5 % of air voids can reduce the strength by 30 to 40 %. As we can see in the above chart, even at the same water/cement ratio strength is different with different compaction accuracies.
How Do You Break Hard Concrete? Breaking hard concrete is easier if you undermine its external support, so dig out underneath it if possible, or use a pry bar to lift it a little at a time, so it's weaker when hit with a sledgehammer or other tool.
Water facilitates the curing and hardening processes. Without it, the chemical reactions needed to form the hard crystals that give the concrete its strength can't take place. Too little water leads to structurally weak concrete, and too much will disrupt effective curing and cause flaking, shrinking, divots or cracks.
Vinegar does not dissolve concrete itself but can degrade the cement that binds concrete together. As a weak, dilute acid, vinegar will cause only minor damage to concrete but can take the shine off polished surfaces. It can, however, be used to remove small amounts of cement from tools.
“Sugar affects both fresh and hardened concrete. Dry sugar has no effect on hardened concrete, but sugar solutions can be very corrosive.” This vulnerability has been turned into an opportunity to safely remove hardened concrete from a variety of surfaces that are otherwise difficult to clean.
Gypsum plays an important role in controlling the rate of hardening of the cement. It is added to concrete and cement to slow down the drying time as cement dries quickly.
The Biggest Enemy of Concrete: Water
When the concrete cures the water in it evaporates. So by nature concrete has a tendency to absorb water. A constant presence of water will weaken the bond of the surface materials. Once that surface is weakened and begins to wear off it opens the concrete to rapid failure.
Concrete has a relatively low tensile strength (compared to other building materials), low ductility, low strength-to-weight ratio, and is susceptible to cracking.
So while you're looking to get rid of those oil stains from the concrete driveway you found WD40 as a solution to remove oil stains but then you start wondering “does WD40 stain concrete?” Yes! It does and that's because WD40 itself acts like an engine oil going inside the concrete leaving it discolored or stained.
The answer is yes, salt does indirectly damage your concrete driveways, patios and sidewalks. Bumps and potholes don't just appear due to regular wear and tear – salt damages concrete over time by causing corrosion to occur under the surface, leading to discolored, cracked and crumbling concrete.
As a gentler cleaner, bleach can't harm concrete's durable material.
While concrete may transform in Coke, the various products that form are all very insoluble, and the phosphates are even less soluble at low pH than the other precipitates.
NIGHT STAIN REMOVAL
Acid based stains such as milk, juice, vinegar may etch the concrete, potentially causing permanent damage to the concrete.
Sugar delays the setting time of cement by up to 1.33 hours at dosage level of 0.06% by weight of cement. No effect on workability, compaction by the use of sugar as admixture in concrete. Higher long-term compressive strength can be achieved in concrete by the use of sugar as admixture.
Baking Soda
Salt and commercial ice-melt formulations can stain — or actually eat away — the concrete around your house. For an effective, but completely innocuous, way to melt the ice on your steps and walkways during those cold winter months, try sprinkling them with generous amounts of baking soda.
Despite the signal word danger on most such labels, gardeners may instead just see vinegar and be careless. Sobering details: In concentrations over 11%, acetic acid can burn skin and cause eye damage, and concentrations of 20% and above are corrosive to tin, aluminum, iron, and concrete and can even cause blindness.
Does concrete take 100 years to cure? No, this is a bit of a myth with the concrete industry. While concrete does continue to harden indefinitely, pore moisture has to drop below a certain level at some point and this isn't typically 100 years.
Although the terms cement and concrete often are used interchangeably, cement is actually an ingredient of concrete. Concrete is a mixture of aggregates and paste. The aggregates are sand and gravel or crushed stone; the paste is water and portland cement.
Pouring concrete over existing concrete is possible as long as you do so properly. When the old concrete serves as the foundation for your new pour, it needs to be a solid one.
Cracking in the structural member – from corrosion, fatigue, chemical attack, construction defects, loading or repeated movement. Loss of strength in the structural material – from corrosion and fatigue of reinforcement; chemical or frost attack in concrete and fire or explosion.