What happens when Sugar is Added to Concrete?


Principle Behind Sugar in Concrete

The Basic Principle followed is the glucose catalytic principle.According to its formula, it belongs to the polyhydroxy group and its surface has strong polarity. This will result in solid-liquid adsorption. Hence the molecular hydroxy group slows the hydration process by hindering the crystal contact and delays tricalcium silicate hydrate reaction.

Remarkable Effect of Sugar on Concrete

The authors elaborated the positive influence and principle of sugar ( ordinary table sugar ) on concrete retarding, liquidity, density, hydration heat, strength and other aspects, introduced good effect, adding ratio and issues needing attention of adding sugar in the process of concrete construction, highlighted advantages of being easy to obtained and with low cost, comparing with other additives, reached the conclusion that sugar is a kind of good additive to be used in concrete construction [Yang Chen, Nanjing University of Technology].

Functions of Sugar in Concrete

The function are:

  • Retarding action on Concrete
  • Increase in Flowability and Compactness
  • Reduction in Hydration Heat and Temperature Cracks
  • Reduction in Hydration Heat and Temperature Cracks
  • Increase in Later Strength of Concrete

Retarding on Concrete

The retarding effect of sugar actually has something to do with the glucose catalytic principle. According to the molecular formula of sugar, it belongs to the polyhydroxy compound. Its surface has strong polarity, thus resulting in solid-liquid adsorption, molecular hydroxyl groups in the cement surface hindered cement hydration process, crystal contact between is shielded, hinders the crystallization of continued growth, changes the structure of the forming process, main changes to delay and delay of three calcium silicate hydrate crystal transformation, following table is the retarding time of concrete mixed with ordinary Portland cement by sugar according to the experimental data from laboratory and field application, in the daytime maximum temperature 31 degrees Celsius on average temperature of 26 degrees Celsius:

Increase The Flowability and Compactness

In terms of concrete pouring construction, concrete is often too viscous (with bad flowability) to be put into formwork operation, such as thin wall slide framework, thin wall concrete board, concrete water pool and etc.. As well as that, in these thin concrete projects, construction quality will be influenced by bad flowability and hard flap. The bad effects are even more serious to water pools with the anti-permeability requirement, grain silos and cement silos with air tightness requirement. If we handle this issue by increasing water amount to increase collapsed slump, it is inevitable that this method does harm to concrete strength and anti-permeability. Instead, we can solve this problem by adding the appropriate amount of sugar.

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