|
|
Phil Sacre. My Credentials.
This page is currently work in progress. I will be adding a lot more knowledge in due course.
-
5 O Levels, an HNC-similar qualification in civil engineering from my years as a soldier in the Royal Engineers, A 2.1 BA (hons) degree, two post-graduate diplomas.
-
While part-time at university earning my two PgDs, I taught first year students on their Construction Management degree, as well as many groups studying for HNDs.
-
A career on big construction sites as a site engineer until 2004, since when I have mainly helped self-builders to build their own basement.
-
In 2012 in particular, I self-studied Advanced Concrete Technology, concentrating on the waterproofing of concrete.
Having exhausted all I could find in the course syllabus books for the Diploma in Advanced Concrete Technology, I attended Kingston University Library many, many evenings after work. Here I found the jigsaw pieces missing from the Diploma set of books.
|
|
|
First of all, I wrote to the editor of an appropriate academic journal, a Cambridge Don, and asked how I might turn my research findings into a MPhil. Not a Doctorate of Philosophy, a PhD, but a Masters level recognition of my research.
He replied that he had just acted as secretary to a study by a working group of the Concrete Society who had published very similar findings. I had just been pipped to the post.
Click here to go to a page I wrote back in 2013 after that research, crediting the Concrete Society more than myself. Here you will find all the sources I use.
What now continues is confirmation by others since, that by the end of 2012, after which no self-builder that built my way ever had a leak, I had worked it all out correctly. High quality concrete and appropriate reinforcement design. Supervision throughout. No 'Products'.
This is the complete email received 15th October 2025, from
|
|
Hi Phil,
As a self-proclaimed Concrete Evangelist, I went down your rabbit hole and ended up with full-on nodding dog syndrome. I have to say, I admire the tenacity of people like you who see through the smoke and mirrors and get back to what actually matters - a watertight concrete design.
I spend much of my time with independent concrete producers forced to keep shelves full of every flavour of "waterproofer" because the CPD entertainers to architects and designers have made them a commodity. I've lost count of how often I've tried to advocate for a properly designed concrete instead of a bucket of fairy dust.
If these systems are truly so miraculous, why do so many of their specifications still call for a C32/40 mix with 350 kg/m³ cement and a w/c ratio of 0.45? That's already dense enough to keep the Ark afloat.
|
I couldn't agree more with your principle that:
-
A very dense, low-permeability concrete (with controlled water content, high cementitious content, proper compaction, curing, and supervision) can act as the waterproofing barrier itself.
-
Many marketed waterproofing admixtures, membranes, or systems tend to mask workmanship defects rather than solve them.
-
And the best admixture on Earth cannot fix a poorly designed, poorly placed, overly wet, or poorly cured concrete element.
Appreciate your work and the clarity of the message. It's refreshing to find someone else who believes that good concrete doesn't need a sales pitch - just sound engineering and a bit of respect for the mix.
All the best, not that far away in Kent.
|
This next email is from Fergus Willmore on 28th April 2022. First of all all he phoned me to express his deep gratitude for the science and other information on my websites.
He was employed by Yorkshire Water to troubleshoot their most difficult problems. For the past 18 months that had been new reinforced concrete water tanks that leaked.
He studied what he could find and talked to who would talk to him, but drew complete blanks.
Eventually he found my web pages and the truth behind the science of building a waterproof structure that would never leak.
This, he told me, was the starting point he needed.
18 months after he started, he sent me 14 attachments of further science he had found. (As well as the two links in his email), making 16.
Some is useful but very heavy stuff, which is why I only give you a flavour and links to the full document to read if you are even sadder than me. The rest is greener solutions not widely available, so I have provided links but no commentary.
His choices of academic and professional papers concentrate on the problems with making concrete greener, the problems with speeding up construction, and the problems with reducing costs.
The general conclusion of his collection of evidence is that a lot of "innovation" reduces the durability of concrete, meaning extremely expensive premature repairs or complete replacement of the structure. For instance, faster setting cement in the USA is why hundreds of thousands of post-war bridge decks are breaking up; whereas older bridge decks are still fully serviceable.
As you read the email, do not read "C35" as in a strength of concrete. He writes C 2 S and C 3 S, which, as he explains, are different calcium silicate compounds that make cement work.
I am quoting one sentence from the email here and on other pages.
As long as the water content is strictly controlled during any pour, then the prospect of water pores is reduced, as excessive water is not left within the mix, to create voids.
This is why my site supervision of concrete pours is so valuable. I am frequently standing in the way of the truck driver, pump operator and labourers trying to add water.
Greetings,
Thank you for all of the information on your website - I found it very useful!
All of this may intrigue you, or it may not…
Summary of 18 months work.
Sorry about the blizzard of info on Cement composition!!
Conjuring all of the above attachments into a handwaving argument…
The Alkaline Reserve is what protects the cement against Carbonation and also the rebar from corrosion. It is the residual Calcium Hydroxide left over from the hydration of C3S (Tri Calcium Silicate) and C2S (Di Calcium Silicate) into CSH (Calcium Silicate Hydrate).
It prevents porosity, by precipitating Manganese and Calcium and Magnesium on contact, within fine pores/cracks, or on the surface, which, to an extent, is termed self-healing concrete.
This is due to maintaining a bulk, and surface, pH above pH8.3.
As long as the water content is strictly controlled during any pour, then the prospect of water pores is reduced, as excessive water is not left within the mix, to create voids.
Modern practise is for a high strength at 28 days product, which does not heat excessively, and is greener than OPC.
For a small variation in clay content, a very sharp change in composition is possible. find it here.
As such, the effort would be to direct towards production of C3S, (TriCalcium Silicate), for a faster early set cement, an easier to mill clinker, a clinker that will easily mill FINE,
which allows for less cement to be used to achieve the same 28 day strength.
With such fineness comes the risk of heat evolution. This may be controlled by adding GGBS.
In turn, the GGBS consumes Portlandite (Calcium Hydroxide) to set, itself, thus reducing the overall heat of set, but also reducing the Alkaline Reserve within the Cement paste.
Older school cement production, with poorer quality control would err on the side of more C2S, albeit with the risk of producing clinker that is much harder to mill.
Under-Limed clinker is better than Over-Limed. find source here.
This means a slower set, so a higher cement content is required for a 28 day strength, but there are no heating problems associated with this mix.
The coarser particle size means slower reaction and no GGBS addition, means more Alkaline Reserve. It also means greater tolerance to water, as the slower reacting grains are not counted in the 28 day strength and may continue to combine with water for some time after initial pour and strength is achieved.
The final part is that C3S is less resistant to Sulphate infiltration than C2S, so one's concrete has a lower paste content, a lower Alkaline Reserve, a lower chemical resistance and consequently a higher porosity, which may develop rapidly.
The addition of soluble (Carbonate) aggregate helps even less. Material that would ideally be inert, when exposed by retreating paste, now dissolves, leaving voids that allow for further water migration into the bulk, ever nearer the precious rebar!
Regards,
F
|
I will now try to explain the technical terms for you.
More examples of putting twice the dose of powder into waterproof concrete.
Here are 3 videos. Very short. 9 seconds, 8 seconds and 7 seconds.
YouTube video 1.
YouTube video 2
YouTube video 3
Both pours in the videos are the ground floor over a basement.
If the floor isn't flat and level you will be walking through puddles while you build the walls.
Back to the Basement Building Questions Answered menu.
|
Back to the Basement Building Construction Manual menu.
|
For a fixed fee of £199 I will answer all your questions by email. More details here.
|
Previous Page
|
|
Next Page
|
|
The Page After That
|
|
|
|
