4207 Slump Too High – Can You Add Cement to Fix It? A Practical Guide to Handling Slump Deviation on Site

Full Product Description:

The slump test result is 190mm. Design says 150mm. The foreman says: “Just add some cement. That’ll dry it up.”

That’s the wrong answer. Adding cement to a wet mix doesn‘t fix it – it creates a new problem. And adding water to a dry mix weakens the concrete permanently.

This guide gives you a simple decision flow for slump deviation:

• What’s acceptable (±30mm)
• What‘s marginal (±31-50mm) – hold and call the supplier technician
• What’s unacceptable (>±50mm) – reject immediately
• The one scenario where you should reject without even thinking (segregation)
• How to correctly handle a dry mix (superplasticiser, not water)
• How to correctly handle a wet mix (extend mixing, assess, or reject)

What‘s inside:

• Slump deviation decision flow – from measurement to decision in 4 steps
• Correct vs incorrect fixes – what works and what fails
• Segregation red flags – spot it, reject it
• Printable decision card – cut it out, put it in your hard hat, carry it on site

Who this is for:

• Site supervisors
• Quality inspectors
• Foremen
• Anyone signing for concrete deliveries

What you‘ll learn:

• Why adding cement to a wet mix is always wrong
• Why adding water to a dry mix is always wrong
• When you can adjust and when you must reject
• How to spot segregation – and why it’s an automatic reject
• What to say to the supplier when the slump is wrong

From the BuildMyAfri library:

This guide is part of a 700+ case study library built for African construction sites. Every article is based on real site experience – no theory, no textbooks.

Product Tags / Keywords:

slump test, concrete slump, slump deviation, concrete quality control, site supervision, concrete acceptance, construction guide, Kenya construction, concrete troubleshooting, concrete testing