Cement Dissolution: Will It Happen, and If So How Quickly? This is a blog about what happens to cement when it is submerged in water and will it dissolve. I have been wondering about this for quite some time because people are always telling me that if you submerge cement in water it will just disappear. I looked around on the internet and found nothing conclusive but did learn a few interesting things.
For instance, Portland cement is made from limestone (calcium carbonate) that has been heated to very high temperatures (about 1500 degrees C) to produce lime (calcium oxide). The lime is then mixed with sand and clay and ground up into a fine powder called Portland cement. The very first step in the production of Portland cement was published by an English bricklayer named Joseph Aspdin in 1824, which consisted of calcinating a mixture of finely divided limestone mixed with clay. He heated the material in a kiln until the water was driven off and then ground it into a fine powder (this process is called sintering).
So what happens if you put this material into water? Well, there are many variables to consider such as the temperature of the water, the pH of the water, and whether or not any other chemicals have
Cement dissolution: Will it happen, and if so how quickly? This blog is about what happens to cement when it is submerged in water and will it dissolve. Cement is a term used commonly in the construction industry to describe a variety of building materials with adhesive and aggregate properties. The two most common types of portland cement are Type 1 (general use) and Type 2 (moderate sulfate resistance). Cement is a binder that when mixed with water hardens over time due to the hydration reaction between the cement powder and water. Hydration of portland cement lowers pH and as a result increases free calcium (Ca) ions in solution. These free Ca ions are what cause cement to dissolve in water. As a result, cement is considered highly soluble with a solubility product constant between 10-5 and 10-6. Cements that have been around for longer or have high concentrations of lime (CaO) will have higher rates of dissolution than cements that are new or contain less lime but these differences may not be significant for short-term exposure. The solubility rate can also vary depending on temperature, pressure, mineralogy, polymers/admixtures, etc., but again this variability may not be significant for short-term exposure
This is a blog about what happens to cement when it is submerged in water and will it dissolve.
When I say that, people ask me “what type of cement?” Portland cement? Calcium aluminate cement? Gypsum cement?
Many types of cements are used in the world, including all of these. The reason most people think of Portland cement when they hear the word “cement” is that it’s so dominant; this is due to its high availability and low cost. But as far as I can tell, there is no reason why any other type wouldn’t dissolve just as well as Portland cement, given enough time and enough water.
The first issue to deal with is: does it dissolve at all? Yes, it does. It dissolves very slowly, but it does. Just not much!
Dissolution of cement paste is a major concern for concrete durability. This paper by Duane Priddy of Priddy Research and Consulting, LLC, looks at the processes involved in the dissolution of cement particles. What happens to cement when it is submerged in water? Will it dissolve, and if so how quickly?
The rate of dissolution has been measured in various ways (see Figure 1). Dissolution can be measured through changes in electrical conductivity, pH, and ion concentration. These factors are related to each other in a way that allows us to look at the dissolution rate as a function of time.
Figure 1: Dissolution Rate vs. Time
This blog will be dedicated to the dissolution of cement in water. Cement is used in many of our everyday lives, we use it to make concrete, mortar and many other things. But did you ever wonder what happens if cement comes into contact with water? The purpose of this blog is to answer that question.
There are a lot of questions that need to be answered. How much weight will the cement lose? Will it dissolve completely? How long does it take for the cement to dissolve? These are just some of the questions I will be looking into.
The research process starts here.
I would like to create a little experiment to see how long it takes for cement to dissolve in water but I have no idea how this is going to work or where to even start.
I also have no idea how much time I am going to put into this project and how much time I am going to spend on it each day.
I will try my best!
Based on the findings in this paper, it is suggested that the dissolution of cement particles in water is a slow process and that the major dissolving agent is carbon dioxide.
The presence of carbon dioxide dissolved in water causes a chemical reaction which results in the formation of additional calcium hydroxide. This calcium hydroxide, in turn, interacts with carbon dioxide to produce calcium carbonate which precipitates from solution (cement). As this precipitation proceeds, more calcium hydroxide is liberated which provides for additional dissolution.
This action appears to be a long-term process and is probably not significant over short periods such as those involved in typical concrete construction projects. However, when cementitious materials are used as components of concrete structures exposed to water for long periods of time, considerations should be given to the possible effects of this chemical action.
Dissolution of cement is not a good thing. Cement is the ingredient in concrete that makes it strong and hard. If it dissolves, then the concrete will crumble and eventually disintegrate. The first question we will try to answer is whether cement dissolves in water.
Chemical composition of cementThe composition of cement varies widely depending on the type of cement used for example, Portland cement, fly-ash based Portland cement, slag based Portland cement etc. The typical chemical composition is given below:
SiO2 – 21%Al2O3 – 5%Fe2O3 – 3%CaO – 64%MgO – 2%SO3 – 1%K2O + Na2O – 1%
The major constituent of cement is calcium silicates (belonging to a category known as hydraulic cements). Calcium silicates are compounds containing Si-O-Ca bonds formed by the reaction between calcium oxide (CaO) and silica (SiO2). Calcium silicates react with water to form calcium hydroxide (Ca(OH)2) and silica gel. This reaction is called hydration or setting process and produces a hard solid mass called hydrated cement paste which imparts strength to