Why water and concrete don’t mix

Published 25 Jul 2017

2 mins read

Updated 29th November 2023

Why water and concrete don’t mix

Water and concrete, rather ironically, don’t mix. Despite the fact that concrete relies on water to trigger the setting process, once set excess moisture will only serve to harm it. There are a few ways that moisture can damage concrete, which serve to demonstrate just how important concrete waterproofing is. Let’s take a look at four of the most common.

Larger gaps between cement particles

If your concrete is made with too much water, the gaps between cement particles will be larger. As the water evaporates and the concrete hardens these gaps will be filled with air – not exactly nature’s strongest material – which serves to weaken the entire structure. The concrete’s compressive strength and durability are affected in a big way; concrete with trapped air levels of just 10% can experience strength reductions of up to 40%.

Reinforced Rust

Reinforced concrete will be strengthened by metal bars running through it. But in wet or humid conditions these reinforcements can actually serve to weaken the concrete. If constantly moist the metal can begin to rust, which expands within the concrete, eventually cracking it.

Microbial growth

The combination of a humid climate, warm temperatures and porous concrete can serve as the ideal breeding ground for microbes which weaken its structure. Mould, bacteria and any other microbial organism can feast on the organic materials that the porous concrete traps. The acidic waste which these microbes leave behind can severely weaken the concrete, particularly in the case of mould.

Temperature differentials

If your concrete is porous and allows moisture to enter, it opens itself up to cracking from within. This is because water expands as it cools. If your concrete is moist and there is a snap frost, the ice will crack the concrete from the inside, severely weakening it.

While it’s got a reputation as one of the strongest materials on the planet, concrete can be affected by one of the most abundant substances on the planet – water – in a surprising amount of ways. It just goes to show the importance of investing in good concrete waterproofing for your slab.

To find out more about concrete waterproofing or for an obligation-free quote, call the friendly team at Titan Waterproofing on 1300 761 219.

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