Cement and GGBS

The potential applicability of several biopolymers, including xanthan gum, diutan gum, acacia gum, modified starch, guar gum and a cellulosic polymer, for maintaining the solid particles of a particulate grout in suspension has been evaluated through static bleeding tests. The grout material investigated was ground granulated blast-furnace slag (GGBS) cement prepared at different water to binder ratio values ranging from 2:1 to 5:1. Among the biopolymers studied, diutan gum and xanthan gum were found to have the highest performance in bleeding prevention at very low concentrations in ranging 0.25–1.0%. A synergy was observed for xanthan gum and guar gum and for xanthan gum and cellulosic polymer combinations. This helps reduce the overall amount of biopolymer required for suspension stabilization. By measuring the zeta potential and viscosity values of the biopolymer-added grouts, the mechanisms underlying the sedimentation inhibitory action of the biopolymers are discussed.

This study investigates the effect of fly ash (FA) and ground granulated blast furnace slag (GGBS) as partial
replacement of cement in the manufacture of concrete. Manufactured sand (M-sand) is used as fine aggregate in the place of
scarce river sand. The grade of concrete used is M20. The cube, cylindrical and prism specimens were cast and subjected to wet
curing. The compressive strength, split tensile strength and flexural strength of concrete specimen was tested at 28 days. The
experimental results indicated that replacement of cement by flyash resulted in decreasing the compressive strength and these
strength values falls below 20 MPa after 30% partial replacement of cement by flyash. Further, the flyash is partial replaced by
GGBS and then experimental tests were conducted. The cement concrete having binder proportions (50% cement, 30% flyash
and 20% GGBS) provides better mechanical performance and optimum results in economical considerations. Hence the use of
major industrial wastes such as fly ash and GGBS is found to be feasible in the production of new sustainable construction
material.

Concrete is one of the major construction material used in the construction now a day. It is a composite material containing cement, coarse aggregate, fine aggregate and water. In the future, fresh water will be very difficult to get and obtain. It is said that in 2024 half of the mankind will live in the areas where fresh water is not enough. Also, UN and WMO are predicting 5 billion people will be in short of even drinking water. The depletion of natural sand deposits and illegal sand mining is a common issue on these days. Extraction of river sand as fine aggregate affect negatively on river ecosystems, navigation and flood control. This paper presents an experimental critical review of existing studies based on the effects of using sea-sand and/or seawater as raw materials of concrete on the properties of the resulting concrete, short and long term strength as well as durability. It has been shown by some researchers that concrete made with sea water and sea sand develops its early strength faster than that of ordinary concrete, but the former achieves a long term strength similar. Attempts were made to over come the problems of using sea water and sea sand in concrete by adding some suitable material. The samples are from cochin, by the means of laboratory tests to assess the compatibility of modifying the samples. Compressive strength, flexural strength and tensile strength test was conducted on the various concrete specimens with various proportion for the comparison analysis. The effort of improving this technology saves fresh water and river, reduces water scarcity. I. INTRODUCTION In the year of 2016, the amount of cement produced in the world reached 4.20 billion tonnes and the estimated concrete production was around 25 billion tonnes. The production of aggregates (including both coarse and fine aggregate) reached about 40 billion tonnes in the year 2015. The consumption of huge amounts of raw materials, mainly river sand and freshwater, in concrete production has raised very serious environmental issues. The depletion of natural sand deposits and illegal sand mining is a common issue these days. Extraction of river sand as fine aggregate impacts negatively on river ecosystems, navigation and flood control. Similarly, the consumption of a great amount of freshwater poses a great challenge due to water shortage in many parts of the world. Besides sand and water, consumption of the other main constituents of concrete, has also caused major environmental concerns, but the present discussion is mainly concerned with alternative solutions for sand and water. The need of desalted sea sand and sea water cause to extra huge production cost. The direct use of both sea-sand and seawater without desalting in concrete production is particularly implemented for marine and coastal projects, for which the supplies of freshwater and river sand are limited where. Several studies agree that in comparison with concrete mixed with fresh water, concrete mixed with sea water increases early age strength and reduces setting time. The concrete produced with seawater using blast furnace slag cement and a low water cement ratio increases the resistance towards chloride penetration. Sea water can be used instead of fresh water where it is not available such as isolated islands and coastal areas. As a result, the topic of seawater sea sand concrete or sea sand seawater concrete has attracted the attention of us. The purpose of this project is to study about the use of sea-sand and seawater as raw materials for concrete to replace river sand and freshwater. In general, concrete cast with seawater but ordinary fine aggregate is referred to as seawater concrete, while concrete cast with sea-sand but freshwater is referred to as sea sand concrete. The demand for manufactured fine aggregates is increasing highly as river sand cannot meet the rising demand of construction sector. The limited supply capacity of natural sea sand cannot meet the supply guarantee needs. Under this circumstances the manufactured sand is impossible. In many countries sea sand has been used for making cement concrete since long time ago, naturally, its technology depends on the research achievement and specific conditions of each country. Therefore, studying the differences in properties of both river and sea sand will give an idea whether sea sand can be altered in such a way that it can be used as a substitute for the depleting river sand. Removing process of river sand from river bed has environmental impacts. The discussions presented in this report have clearly indicated that sea-sand and seawater structures are most attractive in marine/coastal construction, where steel corrosion is a major concern and access to river sand and freshwater is limited but sea-sand and huge amount of sea water are easily available, mainly in island and costal area where fresh water availability is low.

Supplementary cementitious materials (SCM) are the integral part of modern concrete with significant enhancement in concrete performance. Low cost of production, low heat of hydration along with improved mechanical properties encourage the replacement of ordinary Portland cement (OPC) with SCMs to a greater extent. The study focusses on influence of Ground granulated blast furnace slag (GGBS) as SCM in production of concrete paver blocks. Compressive strength, split tensile strength, and flexural strength are the properties under consideration. Improved compressive strength and flexural strength was observed in blended concrete with 20% and 40% GGBS replacement levels.