Influence of non-hydrocarbon substances on the compressive strength of natural rubber latex-modified concrete
Highlights
► Compressive strength test was conducted on natural rubber latex-modified concrete. ► Influence of non-hydrocarbon substances was examined. ► Volatile fatty acids and zinc were found to impair strength of concrete. ► High sludge content and pH value of the latex favor strength development.
Introduction
Polymer latexes are being increasingly used in civil engineering applications as modifiers, especially for the purpose of improving workability, drying shrinkage, strengths characteristics and durability properties of cement products [1], [2], [3]. NRL as a dispersion of poly-isoprene is naturally polymerized by Hevea brasiliensis tree [4]. Most of its properties are therefore determined during the process of natural polymerization rather than controlled as normally is the case with emulsion polymerization.
In its fresh state, NRL comprises 30–40% rubber particles suspended in a serum together with non-rubber substances such as proteins, volatile fatty acids, sludge and some inorganic materials [5]. However, the non-rubber components are in minor quantities amounting to about 6% only [6]. Water is present as a medium of dispersion and this forms the major component [7].
Even though, the first patent with the present concept of polymer latex-modified systems published by Lefebvre in 1924, and subsequent patents throughout 1920s and 1930s used NRL as the modifier, its continuous application was overshadowed by the advent of synthetic latexes [8]. Compositional instability especially coagulation and presence of non-rubber substances are the major factors believed to be responsible for reluctance in its continuous utilization. At present, while coagulation can be avoided by introducing 0.2% or more of ammonia–tetramethylthiuram disulfide/zinc oxide [9], non-rubber substances are still found in NR latexes. It is feared that strength developments in concrete could be affected by the presence of these non-hydrocarbon substances. Indeed, Neelamegam et al. [10] reported strength depreciations associated with concrete modified with NRL.
The objective of the present work is to investigate the role of non-hydrocarbon substances present in NRL on the compressive strength of concrete by conducting chemical analyses on six selected clonal latexes so that chemical properties especially nature and contents of the non-rubber substances are assessed, followed by evaluation of compressive strength on normal concrete (NC) as well as clonally modified concretes. Eventually, the strength being one of the major criterions for assessing qualities of concrete was studied in relation to the chemical analyses results and notable observations were concisely reported. Indeed, identification of the major factors affecting performance of NRL in concrete could provide insight on appropriate measures to be employed so that maximum effectiveness of the latex is ensured.
Section snippets
Materials and mix-design
OPC complying with BS 12:1989 [11] was used throughout. Chemical composition, physical and mechanical properties of the cement are shown in Table 1. Crushed granite stones and naturally occurring river-washed quartz sand are used as coarse and fine aggregates respectively. ASTM sieve No. 4 (4.75 mm) was considered as a demarcation between the two classes of aggregates.
Clonal latexes were supplied by Rubber Research Institute of Malaysia (RRIM) and Sime Darby Research Centre, Malaysia. Four of
Chemical analyses
Results of total solid and dry rubber contents for the individual clonal latexes are shown in Fig. 2. TSC and DRC are normally related in that the later is always part of the former. Thus, DRC is usually less than TSC as demonstrated in the figure. TSC results which include both rubber and the non-rubber substances indicated a wide range; 27.2–45.54%. Indeed, while RRIM 926 revealed an outstanding amount of 45.54%, PB 260 demonstrated a surprisingly low content of about 27.2% only. However, the
Conclusions
Based on the experimental results of this study, the following conclusions were drawn:
- (1)
Generally, compressive strength of NRL-MC is affected by non-hydrocarbon substances normally present in the latex. The chief substances causing strength impairment are volatile fatty acids and metals particularly zinc which appeared to be the most dominant substance among the inorganic substances. In fact, 15.8% compressive strength decrease was observed on specimens containing latex associated with highest
Acknowledgment
The authors gratefully acknowledge the support for this research from Ministry of Science and Technology Malaysia, Research Management Center UTM, MacArthur Fund BUK and Technicians, Faculty of Civil Engineering Universiti Teknologi Malaysia.
References (27)
- et al.
SBR latex modified mortar rheology and mechanical behavior
Cem Concr Res
(2004) - et al.
Development of polymer films by the coalescence of polymer particles in powdered and aqueous polymer-modified mortar
Cem Concr Res
(2003) - et al.
Use of ready-mixed concrete plant sludge water in concrete containing additive or admixture
J Environ Manage
(2009) - et al.
Retardation of cement hydration caused by heavy metals present in ISF slag used as aggregate
Cement Concr Compos
(2008) - et al.
Characterization of products of tricalcium silicate hydration in the presence of heavy metals
J Hazard Mater
(2007) Handbook of polymer-modified concrete and mortars
(1995)- et al.
Elastomeric influence of natural rubber latex on cement mortar at high temperatures using thermal degradation analysis
Constr Build Mater
(2010) - et al.
Natural and synthetic latex polymers
(2002) - Ong EL. Latex protein allergy and your gloves. Malaysian Rubber Board (MRB);...
Structural characterization of natural rubber based on recent evidence from selective enzymatic treatments
J Biosci Bioeng
(2006)
Identification and comparison of natural rubber from two lactuca species
Phytochemistry
Synthetic of highway practice 179 – latex modified concrete and mortars
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