What is the water absorption of the natural stone?

 

Stone water absorption of natural stone's ability to absorb water under standard atmospheric pressure, based on the amount of moisture absorbed by the stone to measure, and is usually expressed as a percentage of quality.

The water absorption of stone is determined by the size and quantity by the voids in the stone, between the particles arranged in a way such. But the stone easily wet the stone, but also exclude factors such as the degree of difficulty of the air gap.

Usually smaller the closer texture hard stone water absorption, for example, hard igneous rock (igneous rocks) very low water absorption, usually no more than 1%; sedimentary water absorption will be much higher, dense sedimentary rock 2-3%, As for the loose texture of sedimentary rocks up to 8%, or even higher.

However, the higher the water absorption of the natural stone, its engineering performance, the worse.

 

Why detect the water absorption of the natural stone?

 

First, we know that natural stone is composed by a variety of minerals, which contain many chemical properties of the active substance, in contact with water and oxygen under conditions of very prone to reactions, such as iron in the stone can easily and The effects of water and oxygen in the reaction of rust, which would destroy the natural stone finishes, as well as change the mineral composition of the stone to reduce its engineering performance.

Secondly, the stone after water absorption will reduce the adhesive force between the particles, it would be a decline in the technical performance of the stone material itself, such as compression strength and bending strength will generally dropped significantly, prone to danger.

Third, the high water absorption of stone, it will increase its weight, weight gain too much will affect the building's original design capacity, affecting the life of the building, increasing security risks.

Fourth, high stone water absorption, so that the water will be along voids stone enters into the building inside the entire building, thus making it in a wet condition, prone to corrosion of various aspects of aging.

The most important is the high water absorption of the stone is prone to freezing and thawing phenomenon. Northern cold weather, when the the stone pores absorb enough moisture, once the temperature dropped below 0 ℃, the stone in the water began to freeze, volume swell. When the ice expansion force is greater than the structural strength of the stone, the stone will produce fragmentation.

There is a part of the natural stone (such as limestone), its easy to water dissolution, if the absorbent is dissolution.

 

How to detect the water absorption of the natural stone?

(Stone water absorption test method)

 

1. Preparation of equipment and measuring tools

① drying oven - the temperature can be controlled in the range of 60 ° ± 2 ℃.

② balance - the largest weighing the quality of 1000g, a sense of volume 10g.

 

Sample and test steps.

 ① sample - sample should be for the side length of 100mm × 100mm, a thickness of the use of thickness. The number of samples for each test was 6.

 ② test steps - first sample with water washed, dried, placed in 60 ° ± 2 ° C constant temperature oven drying 48h to constant weight, and then cooled to room temperature in a desiccator. This time out called quality (W1) readings accurate to 0.01g. 48h after the samples were immersed in 20 ° ± 5 ℃ water, remove the towel wrung gently wipe the moisture of the surface of the sample now called Quality (W2), readings accurate to 0.01g.

 

3 of water absorption calculated W = (W1-W2) / W1 of × 100 wherein the water absorption of the sample of the W-%; W1-samples dried mass, g; mass W2-sample water saturated, g.

 

 (N = 6) the arithmetic mean of the sample water absorption as the varieties of water absorption.

 

Board absorbing report should include the group mean and standard deviation of the sample water absorption. Name of the sample, the species and number. Sample size, quantity. Test conditions. Information about the pilot units.

 

 Translation alwee's blog