**2.1. Introduction**

386 Heat Treatment – Conventional and Novel Applications

**1.2. Research significance** 

**1.3. Research objectives** 

slag mortar.

**1.4. Scope of work** 

cement-slag mortar mix.

The objectives of this research are as follows:

Mortar is a workable paste used to bind construction blocks together and fill the gaps between them. The blocks may be stone, brick, cinder blocks, etc. Modern mortars are typically made from a mixture of sand, a binder such as cement or lime, and water. Based on (ACI, 2006) there are four different types of mortars commonly used in building projects namely Type N, Type M, Type S, and Type O. Type N mortar is a medium strength mortar, which means that it is suitable for use both on indoor projects and on outdoor projects that are above grade. Type M mortar is a high strength mortar. Due to the strength of Type M it is usually used in heavy load bearing walls, although it is also sometimes used in other heavy duty applications like masonry that is below grade or that comes in contact with the earth such as retaining walls or foundations. Type S mortar is also a relatively high strength mortar which is suitable for below grade projects and heavier outdoor projects. Type O mortar is the lowest strength mortar and is suitable only for indoor, lightweight applications. The most commonly used mortars for most home improvement projects are Type N and Type S. Type N is chosen for lighter weight or indoor projects, and Type S for projects that require a heavier duty mortar. All of the different types of mortar are made with the same ingredients. The only difference is the proportions of each ingredient in the mix whether for availability considerations or for minimizing the number of different mortar types on the job site. The OPC-slag mortars can be classified into three groups as

OPC mortars (OMs), slag mortars (SMs), and OPC-slag mortars (OSMs).

forecast the strength behavior of OPC-slag mortars at later ages is established.

Based on the related literature review there is not much research work regarding activation of OPC-slag mortars, and this is the main purpose of this investigation. In this study, the thermal activation method was used. The compressive strength loss was studied in this research at early and later ages. Strength development of OPC-slag mortars without and with use of activation method was also studied for duration up to 90 days and some regression relationships was suggested. Using the suggested relationships a criterion to

• To determine the optimum replacement level of slag and the control ordinary Portland

• To investigate the effects of thermal activation method on both the early and ultimate compressive strengths and also strength loss of the control ordinary Portland cement-

The objective of this study is to use higher percentage of replacement slag as possible without any reduction in mechanical properties of mortar such as compressive strength. Before discussing the activation method, the determination of the optimum level of replacement of slag in OPC-slag mortars is discussed.
