Civil Engineering Program

This paper presents some experimental results on the physical and mechanical properties of reactive powder concrete (RPC) using two different characteristics of densified silica fume (f1 and f2). The silica fume/cement ratio (f/c) varied from 15% to 35% by weight. The flow, the micromorphology by scanning electron microscopy (SEM) and the compressive strength at the ages of 3, 7 and 28 days were studied. The effects of the silica fume agglomerations on the properties of the RPC were considered and discussed. The test results indicated that the properties of RPC depended on the type of silica fume, amount of silica fume and amount of superplasticizer used.

This paper presents the results of an inquiry into the comparative thermal performance and economic viability of interlocking block and clay brick. To this end, two test rooms of 2.4 m width, 2.4 m length and 2 m height were built. The first room was constructed using interlocking block wall whereas the second room used commercial clay brick wall. Data recorded included room temperature, inside and outside surfaces temperatures of all walls, and solar intensity. The experimental results showed that heat conducted better through the interlocking block than through the clay brick. This was not surprising because the thermal conductivity of the interlocking block is 234% higher than the clay brick. However, the cost of interlocking block wall was lower than the clay brick wall by 34.5%. An economic analysis indicates that the payback period of the clay brick in tandem with a 1 ton, split-type air-conditioner depends on the indoor set-point temperature. The payback period extends over a...

This research focuses on evaluating the feasibility of utilizing bottom ash from coal burning power plants as a fine aggregate in cellular concrete with various foam contents. Flows of all mixtures were controlled within 45 ± 5% and used foam content at 30%, 40%, 50%, 60%, and 70% by volume of mixture. Bottom ash from Mae Moh power plant in Thailand was used to replace river sand at the rates of 0%, 25%, 50%, 75%, and 100% by volume of sand. Compressive strength, water absorption, and density of cellular concretes were determined at the ages of 7, 14, and 28 days. Nonlinear regression technique was developed to construct the mathematical models for predicting the compressive strength, water absorption, and density of cellular concrete. The results revealed that the density of cellular concrete decreased while the water absorption increased with an increase in replacement level of bottom ash. From the experimental results, it can be concluded that bottom ash can be used as fine aggre...

The aims of this thesis are to study the fracture behaviour in unreinforced masonry, to carry out a limited experimental program on three-point bending (TPB) masonry panels and to develop a time-dependent fracture formulation for the study of mode I fracture in quasi-brittle materials. A micro-model for fracture in unreinforced masonry is developed using the concept of the discrete crack approach. All basic masonry failure modes are taken into account. To capture brick diagonal tensile cracking and masonry crushing, a linear compression cap is proposed with a criterion for defining the compression cap. The failure surface for brick and brick-mortar interfaces are modelled using a Mohr-Coulomb failure surface with a tension cut-off and a linear compression cap. The fracture formulation, in nonholonomic rate form within a quasi-prescribed displacement approach, is based on a piecewise-linear constitutive law and is in the form of a so-called ?linear complementarity problem? (LCP). The...

For environmental reason, new binders that can be used as Portland cement replacement materials are being needed. Recently, alkali-activated binders (AAB) and geopolymer have found increasing interest. As several research reports have showed that the two new binders are likely to have high potential to be developed and become an alternative to OPC. However, confusion in the classification of both binders is still there. This paper reviews knowledge about AAB and geopolymer including historical background, reaction mechanisms and reaction products. The similarities and differences of both binders are discussed. The application to environmental engineering on hazardous waste management using stabilization/solidification is also described.

From the crisis of global warming, conservation of natural resources and economic growth, buildingstructures and infrastructures with high performances are needed. Research on civil engineering is then highlyfocused on upgrading materials and developing new technologies to earn a brilliant solution both inengineering and global concerns. One of the smart technologies being developed and promoted is the socalled\new hybrid steel structure^ in which steel, the main structural element, and other structural materialssuch as fiber-reinforced polymer (FRP), glass and timber can be utilized appropriately. Ecological and modernstructure styles can be efficiently integrated with this new technology. Therefore, this technology may becomea new fundamental construction in the near future. This paper is, hence, aimed at introducing and discussingabout this new technology.

A unified critical state model has been developed for both clean sand and silty sand using the modified Cam-clay model (MCC). The main feature of the proposed model is a new critical state line equation in the e-ln(p) plane that is capable of handling both straight and curved test results. With this feature, the error in calculating plastic volumetric strain is eliminated in theory. Another crucial feature of the model is the transformed stress tensor based on the SMP (spatially mobilized plane) criterion, which takes into account the proper shear yield and failure of soil under three-dimensional stresses. Additionally, the proposed model applies the intergranular void ratio with the fines influence factor for silty sand. Only eight soil parameters are required for clean sand, and a total number of twelve soil parameters are needed for silty sand.

Shear walls are structural systems which provide stability to structures from lateral loads like wind, seismic loads. As shear wall resist major portions of lateral loads in the lowest portions of the buildings and the frame supports the lateral loads in the upper portions of the building which is suited for soft storey high rise building. The properties of these seismic shear walls dominate the response of the building and therefore, it is important to evaluate the seismic response of the walls appropriately. In this present study, main focus is to determine the solution for shear walls behavior in multi-storey building. Effectiveness of shear walls has been studied with the help of six different models. Model one is bare frame structural system, model two is dual frame structural system and model three is a complete shear wall structural system with internal walls in y-direction and model four is a similar model having internal shear walls in x-direction, model five is again a dual frame having columns at exterior and shear walls in interior placed in y-direction and model six is also an dual frame structure having columns at exterior and shear walls at interior placed in x-direction. An earthquake load is applied to a building of G+15 stories located in zone III, type of soil II and various other factors are considered. Parameters like displacement and storey drift are calculated in all the cases replacing column with shear walls and their locations.