What Are The Four Different Moisture Conditions Of Aggregates?

What is SSD condition of aggregate?

SSD stands for saturated surface-dry and it describes a condition that a concrete surface must be brought to when a cement product is to be applied to it.

The surface is SSD when the substrate is saturated with water, filling the voids in the substrate’s aggregate, but the outer surface is devoid of free water..

What is critical moisture content?

The critical moisture content is the average material moisture content at which the drying rate begins to decline. A prototype drying test should be conducted to determine the critical moisture content. … The critical point (B) occurs when the superficial moisture has evaporated. In porous solids point B of Fig.

How do you find moisture state?

Moisture States: … AC = (WSSD – WOD) / (WOD) x 100% … Effective Absorption: … EA = (WSSD – WAD) / WSSD x 100% … Wabs = (EA) Wagg … Surface Moisture: … SM = (Wwet – WSSD) / WSSD x 100% … Wadd = (SM) Wagg

What are the 4 major moisture conditions for aggregates?

In general, there are four aggregate moisture conditions:Oven-dry (OD). All moisture is removed by heating the aggregate in an oven at 105°C (221°F) to constant weight (this usually constitutes heating it overnight). … Airdry (AD). … Saturated surface dry (SSD). … Wet.

Which condition moisture level of aggregate is considered for concrete mix?

SSD stateThe SSD state is the best choice as a reference state for the following reasons: It represents the “equilibrium moisture” state of the aggregate in concrete; that is, the aggregate will neither absorb water nor give up water to the paste.

What is moisture content in coarse aggregate?

The moisture content in aggregate is used to determine the binder content for HMA during production of the mixture in a plant. The procedure requires that a known amount of aggregate be obtained, the aggregate heated to remove the moisture, and the percentage of moisture determined.

What is the full name of SSD?

SSDs got their name—solid state—because they have no moving parts. In an SSD, all data is stored in integrated circuits.

What are the different methods used in the determination of moisture content of aggregates?

There are three commonly used test methods for performing moisture content tests of normal-weight and lightweight aggregates. ASTM C566, “Standard Test Method for Total Evaporable Moisture Content of Aggregate by Drying,” is applicable to both fine or coarse aggregate and is the most commonly used procedure.

What is the ideal aggregate moisture state?

1 – 2%Absorption and Surface Moisture The range for most normal-weight aggregates is 1 – 2%.

What is aggregate absorption?

Aggregate absorption is the increase in mass due to water in the pores of the material. Aggregate absorption is a useful quality because: High values can indicate non-durable aggregate. Absorption can indicate the amount of asphalt binder the aggregate will absorb.

Is SSD waterproof?

This is a huge plus in its column, as most SSDs are not waterproof. Additionally, the SE730 is MIL-STD-810G 516.6 shock-proof certified, which means it can sustain a drop of up to four feet onto a hard surface.

What is the consequence of using very dry aggregates?

Even if the concrete is tested at the plant and the workability is acceptable, dry aggregates can increase the risk of water being added at the point of placement. Since the absorption of water from the paste by aggregates that are drier than the SSD condition takes time, they can cause slump loss in transit.

How much percentage does aggregate occupies in a concrete mix?

Aggregates, which account for 60 to 75 percent of the total volume of concrete, are divided into two distinct categories–fine and coarse. Fine aggregates generally consist of natural sand or crushed stone with most particles passing through a 3/8-inch sieve.

How does moisture content affect concrete?

How Moisture Affects Concrete Strength. … Similarly, increased moisture levels reduce the concrete’s compressive strength and durability. As concrete’s surface area increases, particularly with the addition of fine aggregates, so does the demand for water. The increased water leads to a higher water-to-cement ratio.

Why is concrete tested in saturated conditions?

As the specimen degrees of saturation increased, the compressive strength fell. However, at nearly saturated condition, an increase in compressive strength can be found. The aim of this study is to evaluate the moisture effect on the strength of concrete specimens that has completely cured.

Do you need to justify the moisture content of aggregates How?

It’s important to determine the moisture content of aggregate prior to mixing, because it affects the proportion of mix water needed to achieve the desired water/cementitious materials ratio.

Is code for silt content?

Silt Content Test for Sand (Fine Aggregate) – Civilology.

How do you test moisture content?

How is Moisture Content Tested? The basic method is to carefully weigh the specimen in its original state, drying the water contained in the specimen, then re-weighing. Precisely HOW this is done depends upon the material.

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