Search Results for: control joint

Four rectangular concrete slabs with handwritten markings

Chloride Ion Testing in Old Slabs: When Salt Exposure Is the Real Problem

Introduction Chloride ion testing in old slabs is a way to find out whether salt exposure is the real problem behind concrete issues. It helps separate chloride-related damage from other moisture or subfloor failures. In plain terms, it’s part of diagnosing why a floor isn’t performing as you’d expect. Many times, moisture problems drive cracking, […]

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Worker pouring concrete slab with shovel and chute

Rapid Chloride Permeability (RCPT) and Alternatives: What “Low Permeability” Really Means

Introduction RCPT is a test that measures how fast chlorides pass through cured concrete. It’s a practical yardstick for judging how resistant your concrete may be to corrosion of embedded steel. This article breaks down what low permeability really means in plain language for DIY projects. We’ll cover the basic steps you’d see in an

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Hands cutting small blue glass mosaic tiles with a knife

Using Crushed Glass as Aggregate: ASR Risk, Mitigation, and Surface Finish

Introduction Crushed glass as aggregate is using recycled glass pieces as the rock substitute in concrete. There is an alkali-silica reaction risk with crushed glass, which varies with glass type, particle size, and the concrete mix. Always check product labels, supplier instructions, and local rules for ASR guidance and suitability. Mitigation strategies include choosing less

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Stacked hollow core concrete slabs outdoors

Using Recycled Concrete Aggregate in Concrete Slabs

Introduction Recycled concrete aggregate (RCA) is processed concrete from demolition that is reused as aggregate in new concrete. It can be suitable for a slab, but it is not interchangeable with virgin aggregate: attached mortar usually makes it more absorptive, lower in specific gravity, and more variable. Use RCA only when the project specification, building

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Electric drill mixing cement in bucket outdoors

Viscosity-Modifying Admixtures (VMA): Stopping Segregation in Flowable Mixes

Introduction Viscosity-modifying admixtures (VMAs) help concrete stay workable without segregating. They slow down the mix’s tendency to separate into heavy cement slurry and lighter aggregate. Use them when you plan long pours, thick slurries, or hot weather. Choose a VMA based on the mixer and concrete type, and follow the label directions. Test a small

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Stacked precast concrete hollow core slabs outdoors

Internal Curing With Lightweight Aggregate: Reducing Shrinkage in Thin Slabs and Countertops

Introduction Internal curing with lightweight aggregate is a method that uses porous, low-density aggregate inside the mix to keep moisture available for hardening. This approach helps manage moisture in thin slabs and countertops as they cure, especially when you’re working with limited thickness. Always follow the material instructions and local rules to ensure proper use.

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Trowel mixing wet cement mortar in a large container

Shrinkage-Compensating Cement: Where It Shines, Detailing Rules, and DIY Reality

Introduction Shrinkage-compensating cement is a concrete mix designed to offset shrinkage as it cures. In DIY projects, it helps reduce cracking on slabs and pads. Use it when you expect movement or large flat surfaces; check product instructions for mixing and cure guidance. For rules and specifications, follow the manufacturer’s directions and any local rules.

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Stacked precast concrete hollow core slabs outdoors

Chloride Penetration in Concrete: Why Coastal Slabs Fail and How to Slow It Down

Introduction Chloride penetration in concrete is the inward movement of chloride ions from the environment into the concrete and reinforcement area. In coastal areas, salt spray, moisture, and wet-dry cycles push chlorides into the concrete matrix. This can lead to corrosion of reinforcing steel and reduce the structure’s long-term durability. To slow chlorides down, choose

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concrete compression test cube inside testing machine

DIY Slump Test: How to Make a Slump Cone and Read the Results

Introduction A slump test measures the workability of fresh concrete by using a cone and watching how much it settles. Key takeaways Understand the slump test measures concrete consistency by observing cone collapse height. Check tools: slump cone, trowel, sampling scoop, and clean curing surface. Follow a step-by-step procedure to ensure consistent results and repeatability.

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