Portland, Blended and Other Hydraulic Cement

Concrete Technology

Introduction

A cement is a binder, a substance used for construction that sets, hardens and adheres to

other materials, binding them together.

Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together.

Cement is used with fine aggregate to produce mortar for masonry, or with sand and gravel

aggregates to produce concrete.

Cements used in construction are usually inorganic, often lime or calcium silicate based,

and can be characterized as being either hydraulic or non-hydraulic, depending upon the

ability of the cement to set in the presence of water

Non-hydraulic cement will not set in wet conditions or underwater; rather, it sets as it dries and reacts with carbon dioxide in the air. It is resistant to attack by chemicals after setting.

Hydraulic cements (e.g., Portland cement) set and become adhesive due to a chemical reaction between the dry ingredients and water.

The chemical reaction results in mineral hydrates that are not very water-soluble and so are quite durable in water and safe from chemical attack.

This allows setting in wet condition or underwater and further protects the hardened material from chemical attack.

Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout.

It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum.

Portland cement is caustic, so it can cause chemical burns. The powder can cause irritation or, with severe exposure, lung cancer, and can contain some hazardous components; such as crystalline silica and hexavalent chromium.

Environmental concerns are the high energy consumption required to mine, manufacture, and transport the cement; and the related air pollution, including the release of greenhouse gases (e.g., carbon dioxide), dioxin, NOx, SO2, and particulates.

https://en.wikipedia.org/wiki/Cement

https://en.wikipedia.org/wiki/Portland_cement

Type of Portland CementType Designation Remark

Type I Normal general-purpose cement suitable for all uses where the special properties of other cement types are not required.

Type IA Normal, air-entraining

Type II Moderate sulfate resistance used where protection against moderate sulfate attack is necessary.

Type IIA Moderate sulfate resistance, air-entraining

Type II MH Moderate heat of hydration and moderate sulfate resistance

manufactured to generate heat at a slower rate than Type I or most Type II cements by limiting the heat index to a maximum of 100.

Type II (MH)A Moderate heat of hydration and moderate sulfate resistance, air-entraining

Type III High early strength provides strength at an earlier period than normally expected.

Type IIIA High early strength, air-entraining

Type IV Low heat of hydration used where the rate and amount of heat generated from hydration must be minimized. It develops strength at a slower rate than other cement types.

Type V High sulfate resistance used in concrete exposed to severe sulfate environments – principally where soils or groundwaters have a high sulfate content. It gains strength more slowly than Type I cement.

Source : SNI 2847:2013, Persyaratan beton struktural untuk bangunan gedung

Source : SNI 6880:2016, Spesifikasi beton struktural

Blended Hydraulic Cement

Blended hydraulic cements are produced by intimately and uniformly intergrinding or blending two or more types of fine materials.

The primary materials are portland cement,slag cement, fly ash, silica fume, calcined clay, other pozzolans, hydrated lime, and preblended combinations of these materials

ASTM C595 recognizes three primary classes of blended cements as follows:• Type IS (X), Portland blast-furnace slag cement• Type IP (X), Portland-pozzolan cement• Type IT(AX)(BY), Ternary blended cement

SNI 0302:2014, Semen Portland Pozzolan

No Kode Keterangan

1 IP-U Semen portland pozzolan yang dapat digunakan untuk semua tujuan pembuatan adukan beton.

2 IP-K Semen portland pozzolan yang dapat digunakan untuk semua tujuan pembuatan adukan beton, semen untuk tahan sulfat sedang dan panas hidrasi sedang

3 P-U Semen portland pozzolan yang dapat digunakan untuk pembuatan beton dimana tidak disyaratkan kekuatan awal yang tinggi

4 P-K Semen portland pozzolan yang dipergunakan untuk pembuatan beton dimana tidak disyaratkan kekuatan awal yang tinggi, serta untuk tahan sulfat sedang dan panas hidrasi rendah

Performance Based Hydraulic Cements

All portland and blended cements are hydraulic cements. “Hydraulic cement” is merely a broader term.

Cements meeting the requirements of ASTM C1157 meet physical performance test requirements, as opposed to prescriptive restrictions on ingredients or cement chemistry as found in other cement specifications.

ASTM C1157 provides for six types of hydraulic cement as follows:1. Type GU, General use2. Type HE, High early strength3. Type MS, Moderate sulfate resistance4. Type HS, High sulfate resistance5. Type MH, Moderate heat of hydration6. Type LH, Low heat of hydration

In addition, these cements can also include an Option R – Low Reactivity with Alkali-Reactive Aggregates – specified to help control alkali-silica reactivity.

Type Remark

GU general purpose cement suitable for all applications where the special properties of other types are not required.

HE provides higher strengths at an early age, usually a week or less. It is used in the same manner as Type III portland cement, and has the same 1- and 3-day strength requirements.

MS used where precaution against moderate sulfate attack is important. It is used in the same manner as Type II and II(MH) portland cement. Like Type II and II(MH), Type MS cement concrete must be designed with a low water-cementitious materials ratio to provide adequate sulfate resistance.

HS used in concrete exposed to severe sulfate action – principally where soils or ground waters have a high sulfate content. It is used in the same manner as Type V portland cement. As noted previously, low water-cementitious materials ratios are criticallyimportant to assure performance of concrete exposed to sulfate exposures.

MH used in applications requiring a moderate heat of hydration and a controlled temperature rise. Type MH cement is used in the same manner as Type II(MH) portland cement.

LH used where the rate and amount of heat generated from hydration must be minimized. It develops strength at a slower rate than other cement types. Type LH cement is intended for use in massive concrete structures where the temperature rise resultingfrom heat generated during hardening must be minimized. It is used as an alternative to Type IV portland cement or in the same manner as a Type IP(LH) or IT(P≥S)(LH) blended cement.

Home Work 01

• Find ACI 225R-99 (reapproved 2009), Guide to the Selection and Use of Hydraulic Cements.

• Write on your own, what, why, when, where and how, to select the hydraulic cement, as well as the key aspect on selecting and using hydraulic cement.

• Collect your work 48 hours after this class!• Thank you.