> For the complete documentation index, see [llms.txt](https://alchemco.gitbook.io/alchemco-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://alchemco.gitbook.io/alchemco-documentation/acceleration-guide.md).

# Acceleration Guide

The purpose of acceleration is NOT to achieve baseline performance with regard to the ETT system. The ETT reaction is comprised of enzymes, water, and calcium, which react together to form the waterproof material residing in the concrete matrix.

Acceleration is an addition of calcium into the substrate to jumpstart the reaction process and increase the waterproofing performance timeline.

## Required vs Optional

**Acceleration is optional** under most application scopes, especially when aesthetics is of great importance.

Acceleration is required for:

• Water-retaining structures

• Carbonated concrete (even in bridge applications)

• Structures that exhibit excessive Alkali-Silica Reaction (ASR)

• Instances where material may escape before reacting

> o *(see Crack Identification, Evaluation & Treatment)*

• When reaction speed must be increased

• When concrete conditions slow down the chemical reaction

• Through cracks

> o *(see Crack Identification, Evaluation & Treatment)*

• Concrete on metal decks

> o *(see Crack Identification, Evaluation & Treatment)*

*Split slab structures*

*(see Crack Identification, Evaluation & Treatment)*

Old concrete structures

Refurbishment projects

Older buildings

Aged concrete infrastructure

Severe problem areas

Heavy cracking

Honeycombing

Leak-prone areas

Acceleration may not be necessary for:

New concrete

Concrete less than two (2) to three (3) years old typically contains enough calcium to support the natural reaction.

Large surface areas

> o Large areas may be unnecessary and increase material cost.

• Cost-sensitive projects

> o Utilizing accelerators only in localized problem areas will save money under tight cost constraints.

• Exposed concrete finishes

> o Acceleration may cause surface whitening on newly finished concrete surfaces. If the concrete surface is the final architectural finish, acceleration should be used carefully or avoided entirely

NOTE: For historical / heritage protected buildings, please use caution with any Alchemco accelerator product. *(see Aesthetic Considerations)*

## Types

We offer two types of Accelerators – ACRtec Surface Accelerating Agent Concentrate and ACRtec Crack Accelerating Agent.

When using the concentrate version of the ACRtec Surface Accelerating Agent, it shall be diluted with clean water utilizing the following mix ratio:

• One (1) part product to twenty (20) parts clean water.

## Sequence

ACRtec Surface Accelerating Agent must be applied at least 24 hours AFTER the ETT product has been sprayed. After the 24 hours have passed, you may apply ACRtec Surface Accelerating Agent at any time on any given day (no maximum wait time).

The same application rate and spray methodology outlined in the *ETT Application Procedure* should be utilized when applying Surface Accelerating Agent.

Water misting shall follow in the same manner.

*(see Coverage Rate & Spray Methodology)*

## Aesthetic Considerations

When taking into account aesthic considerations, it is important to understand that the use of acceleration may result in a visual whitening that resides in the very surface level layer of the concrete matrix.

It’s important to note that this whitening does NOT affect product performance in any way, shape, or form and is purely cosmetic in nature.

Rather than a failure, it is just a byproduct of how fast the reaction is occurring.

Common causes may include:

• Over-application of accelerator

• Surface saturation / low absorption

• Insufficient time allowed for ETT absorption / applying accelerator too soon

• High concentration / improper dilution

If aesthetics is a concern, it is recommended that a 4’x4’ test area be treated prior to assess potential whitening. If whitening is observed, the accelerator may be diluted down and another 4’x4’ area be retested.