Effect of Pozzocrete as Partial Replacement with Cement in Mortar

The International Conference on Civil Infrastructure and Construction

This study investigates the effect of Natural Pozzolana (NP) and Fly Ash (FA) substitutes on concrete's mechanical and microstructural properties. Mixes containing 10 - 50 % cement substitute ratios were prepared and tested for flexure and compressive strength after 28 days of curing. Then, qualitative microstructural analysis was performed using Scanning Electron Microscope (SEM). In terms of compressive strength, the mixes containing only 10 % replacement ratios of both NP and FA showed an improvement of 10 % compared to the plain control mix. On the other hand, all mixes containing FA could attain at least a 25 % development in their flexural strength compared to the control mix. The microstructural analysis illustrated that adding FA and NP enhances cement hydration by improving the formation of dense hydration products such as calcium silicate hydrate (C-S-H) and calcium hydroxide (C-H), which are mainly responsible for the performance of the improved mechanical properties ...

2019

Typical site projects in Malaysia use large amount of cement in the construction for concreting work and mortar production. Excessive usage of cement increases dust concentration around the construction project which contributes to severe surrounding air pollution and adverse health effects. Therefore, this study was conducted to investigate the potential of pozzolanic material as admixture to partially replace cement in concrete as a mean of producing more environmental friendly cement products. The content of fly ash as partial replacement of ordinary portland cement is investigated by weight. The workability of the fresh concrete mixtures was evaluated using slump test while compressive strength of cubes concrete were evaluated at 7, 14 and 28 days. The optimum compressive strength at all ages of testing was obtained at 10% replacement. Workability decreased with an increased in replacement percentage of fly ash. The results therefore shows that fly ash as pozzolanic materials ca...

Fly ash is one of the residue generated by coalcombustion and is composed of the fine particles and showing cementitious property. Fly ash as a Pozzolana results in significant enhancement of the basic characteristics of concrete in both fresh and hardened states. This report investigates the effects of the fineness and replacement ratio of fly ash on the temperature rise, setting time, and compressive strength. This report shows that the fineness, has the significant effect on compressive strength of mortar not the chemical composition. The mortars with finer fly ashes gained higher compressive strength than those with the coarser ones. Fly ash is reduce heat of hydration in concrete. It improved impermeability of concrete mass increases resistance against ingress of moisture and harmful gases. Fly ash in cement concrete as a partial replacement of cement as well as an additive so as to provide an environmentally consistent way of its disposal and reuse. Converting released lime from heat of OPC into additional binding material contributing additional strength to concreate mass. Pore refinement due to reaction between fly ash and liberated lime improving impermeability.Role in the rheology, adhesiveness and strength of mortar, and key parameter with the fly ash replace by cement.

As global demand for mortar follows a growth in this century, energy-efficient, economical and durable building materials are essential for sustainable construction practices. In the present investigation fly ash and lime is replaced with cement in different proportions to study various properties like water demand, compressive strength, split tensile strength on different mortar specimens. Specimens were tested on 7 th and 28 th day of curing.

Processed fly ash is investigated for its use as a replacement of cement in cement mortar as it behaves as a pozzoloana. It may make an important contribution towards decreasing the adverse effect of the disposal and the dumping of fly ash on the environment. The results show that richer mixes gives higher values of compressive strength for cement replacement with fly ash up to 50%. The test results show that the replacement of cement by fly ash at level of 50% by weight has a significant effect on the compressive strength of the mortar blocks as compared with the control sample because of pozzolanic nature of Fly ash. Further, a study is made on tension, surface morphology and chemical composition of cement mortar to strengthen the result. Pozzolanic reactivity of this waste open the possibilities for the use of this material in mortars. The paper presents useful data for the coal manufacturing industry and mortar manufacturing companies in terms of minimizing the cost and using eco-efficient materials.

The filler effect of pozzzolanic materials is defined as proper arrangement of small particles into the microstructure that fill the voids and contribute towards improvement of compressive strength without any chemical reaction. This effect of pozzolan plays a vital role for the production of high strength mortar. The filler effect is dominating when pozzolan particles are in chemically inactive form. The individual contribution of physical and chemical effect in concrete and mortar still not determined. Several studies have been found in the published literature on finding the filler effect of pozzolans by replacing cement with chemically inactive materials which size is same as pozzolans. The chemically inactive materials used in previous studies are carbon black, limestone filler and ground river sand, which used bigger range size of replacement percentages (like 5%, 10%, 15% or 10%, 20%, 30%etc). However in this study, lower range size of replacement percentages (like 2.5%, 5%, ...

This paper discusses the effects of using different pozzolonic materials as a partial cement replacement material in mortar mixes. An experimental study of mortar made with Ordinary Portland Cement (OPC) and 12% of OPC, replaced by different pozzolanic materials such as fly ash, rice husk ash, silica fumes, Calcined Clay (Grog) and Slag (GGBS) were tested for the strength and durability properties to determine the effect of these materials on mortar properties and compared to control mortar mix.

Pakistan Journal of Engineering and Applied Sciences, 2016

Concrete is probably the most extensively used construction material in the world. However, environmental concerns regarding rapid consumption of natural resources and CO2 emission during cement manufacturing process have brought pressure to reduce cement consumption by the use of cement replacement materials (CRMs). The utilization of calcined clay (metakaolin) and silica fume in concrete has received considerable attention in recent years. Brick powder has not got much popularity with respect to strength enhancement but it is effective to reduce drying shrinkage. The following study has been focused to determine the performance of locally available metakaolin, silica fume and brick powder as CRMs in concrete. This study focuses on compressive strength, drying shrinkage and sulfate attack properties of the concrete. Concrete cubes were used for compressive strength determination and mortar prisms for determination of drying-shrinkage and sulfate attack. 5%, 10% and 15% replacement ...

ABUAD International Journal of Natural and Applied Sciences

This paper presents the properties of mortar and concrete with NBRRI pozzolan as partial replacement of cement. In this research, NBRRI pozzolan from NBRRI and local cement (Dangote) are used. Firstly, chemical composition of NBRRI pozzolan and Dangote cement are analyzed. And then the physical properties of local materials used in this research are determined according to ASTM procedure. Partial replacement percentages of pozzolan are considered 10%, 20%, 30% and 40%. The strength of mortar and concrete with NBRRI pozzolan (0%, 10%, 20%, 30%, and 40%) is tested at 7 days, 14 days and 28 days. From the trial mix design, the water-cement ratio (0.555) is obtained by using the least square method. To get target strength (4000 psi), by using water-cement ratio (0.555) and 68% of maximum aggregate size (20 mm), the concrete mix proportion (1:1.9:3) is obtained. The compressive strength of concrete with various percentages of NBRRI pozzolan at 21 days and 28 days are more than 7 days and...

This study has examined the effect of fly ash used as replacement addition (in the quantities of 0-40 mass %) to the Ordinary Portland cement (OPC) (type CEM I 42,5R) on the setting time in the system of paste, compressive strength development (w/s = 0.475-0.5, t = 20°C) and on drying shrinkage of cement mortars (t = 20°C, RH ≥ 55 %). Enlarged addition of fly ash affects extension of setting time and also affects reducing of the water, needed to achieve normal consistency. The increased addition significantly improves resistance to drying shrinkage throughout the measurement period. On the other side, increased amount of added fly ash reduces early strengths of cement mortars. In the later hydration stages, when pozzolanic reaction takes place, the strength difference between samples made with and without addition of fly ash decreases. The effect of the pozzolanic reaction, determined by using TG/DTA, can be observed after 60 days of hydration. A detailed chemical (X-ray diffraction), thermogravimetric and morphological (scanning electron microscope (SEM)) analyses of the hydrated samples of mortars are presented.